Glossary / O

Psychology terms starting with O

740 terms with short definitions. Study these as flashcards

Oabbreviation: In psychophysical testing, this abbreviation marks the observer, the person giving the judgments.
O dataabbreviation: Other data are reports about a person supplied by people who know them, such as friends or relatives.
O variableabbreviation: An organic variable is an internal condition or process that works with an outside stimulus to shape a response.
O-X-Oabbreviation: A research notation shows one group being measured, receiving an intervention, and being measured again.
O’Connor v. Donaldsonnoun: A 1975 Supreme Court decision barred confinement based solely on mental illness when a nondangerous person can live safely outside.
O＆Mabbreviation: Orientation and mobility involves knowing one's location and moving safely, with training supporting people who have visual impairments.
OAabbreviation: Overeaters Anonymous is a voluntary peer support organization using twelve steps to address compulsive eating.
OAEsabbreviation: Otoacoustic emissions are faint sounds generated inside the cochlea that can be recorded to assess its function.
Obamacarenoun: An informal name identifies the 2010 Affordable Care Act, a United States law that changed health insurance and care.
obediencenoun: Following a direct order from someone seen as having authority, such as a parent or boss.
obesitynoun: Having too much body fat raises health risks and can result from genes, habits, environment, or illness.
objectnoun: A person, thing, or situation that someone notices, reacts to, thinks about, or relates to.
Object Assembly testnoun: A subtest in earlier Wechsler intelligence scales asks people to fit separate pieces together into recognizable objects.
object cathexisnoun: Classical psychoanalysis proposes that mental energy can be invested in people, interests, or goals beyond oneself.
object choicenoun: Psychoanalytic theory describes choosing someone as the focus of one's love, desire, or proposed mental energy.
object colornoun: A perceived color appears to belong to a solid thing, such as the green of a leaf.
object constancynoun: Object relations theory proposes that children develop lasting attachment to a caregiver despite absence, frustration, or unmet wishes.
object displaynoun: A visual display combines several measurements into one meaningful shape whose changes reveal a system's condition.
object identitynoun: A developing understanding recognizes that something remains the same individual object even when its appearance or form changes.
object languagenoun: A programming language organizes instructions around data objects that can perform operations and change their own stored information.
object learningnoun: Learning connects different features of the same thing, such as its appearance and its flavor.
object libidonoun: Classical psychoanalysis proposes that people direct mental or sexual energy toward someone or something beyond themselves.
object lossnoun: Psychoanalytic theory describes losing a valued person as an experience connected with separation anxiety and grief.
object lovenoun: Psychoanalytic writers proposed that affection toward someone else comes from the ego, which handles reality, rather than instinctual drives.
object of consciousnessnoun: Anything someone consciously experiences, including a sight, feeling, imagined scene, or awareness of themselves, can occupy this role.
object of instinctnoun: Classical psychoanalysis proposes that a person, thing, or behavior can be sought to satisfy an instinctive drive.
object permanencephrase: Understanding that things still exist even when they cannot be seen, heard, or touched.
object playnoun: Play centers on handling things, such as stacking blocks, moving toys, or arranging everyday items.
object relationsphrase: How a person relates internally and outwardly to important others and things, real or imagined.
object relations psychotherapynoun: This psychoanalytic therapy explores how early relationships and imagined experiences shape a person's inner pictures of important people.
object relations theoryphrase: A psychodynamic view that early relationships shape personality through internal mental pictures of self and others.
object-based attentionnoun: Visual attention selects a particular object as its focus instead of mainly selecting a position in space.
object-location memorynoun: This memory ability lets someone recall where particular things are or where they were previously placed.
object-superiority effectnoun: People judge briefly shown lines more efficiently within drawings suggesting three dimensions than within flat figures.
objectificationnoun: An abstract idea is treated as if it were a concrete thing with an actual physical existence.
objectiveadjective: Based on observable facts and not shaped by personal feelings, opinions, or bias.
objective anxietynoun: Anxiety arises in response to a recognizable real danger and can prepare someone to protect themselves.
objective competitive situationnoun: Observers evaluate a person's or team's performance against another competitor's performance or a standard of excellence.
objective elaborationnoun: Someone thinks through a message and forms judgments mainly from the quality of its reasoning and evidence.
objective indicatornoun: An independently recorded measurement provides evidence about something without relying directly on a person's opinion or rating.
objective priornoun: In Bayesian analysis, an initial probability distribution for unknown values is based on earlier research before current data are considered.
objective psychologynoun: This approach studies mental life through measurable behavior and other events that researchers can observe.
objective psychotherapynoun: Benjamin Karpman's historical therapy used entirely written exchanges between client and therapist to try to reduce personal influence.
objective realityphrase: The world outside your mind that exists whether or not anyone notices or believes it.
objective referencenoun: A word or idea is connected to another concept or to something that exists in the world.
objective responsibilitynoun: Piaget proposed that younger children judge wrongdoing mainly by its physical results, giving little weight to intentions.
objective scoringphrase: Using a fixed answer key or formula so different raters give the same test score.
objective self-awarenessnoun: Someone turns attention toward themselves, evaluating their beliefs and actions against personal standards or ideals.
objective setnoun: Gestalt psychology describes how visually clear groups keep appearing grouped even after rearrangement makes their organization uncertain.
objective testnoun: An assessment uses questions with predetermined correct answers, allowing scoring by fixed rules without a scorer's personal interpretation.
objectivismnoun: This philosophical position holds that claims about reality can be true or false independently of anyone's personal viewpoint.
objectivitynoun: Basing judgments on facts and observations instead of personal feelings, beliefs, or bias.
objectivity illusionnoun: People tend to believe their own judgments are fairer, clearer, and less influenced by bias than other people's judgments.
obligate carriernoun: Family inheritance evidence establishes that someone carries a particular genetic variant even without a direct genetic test.
obligation schemanoun: A proposed set of learned reasoning rules helps people recognize when a particular condition makes an action required.
obliqueadjective: Graph axes meet at angles other than ninety degrees, allowing statistical factors to represent related patterns.
oblique rotationnoun: A factor analysis method adjusts the orientation of underlying factors to clarify patterns while allowing those factors to correlate.
OBMabbreviation: Organizational behavior management applies behavior analysis in workplaces to improve performance through changes such as training, feedback, and rewards.
obnubilationnoun: Conscious awareness becomes clouded or greatly reduced, making surroundings harder to understand and responses less clear.
obscenitynoun: Words, images, gestures, or writing are judged to seriously offend a community's standards of acceptable expression.
obscurantismnoun: Someone opposes inquiry and the spread of knowledge, especially when new understanding challenges strongly held beliefs.
observationnoun: Careful watching of behavior or events to gather data or make conclusions.
observation coding systemnoun: Researchers use clearly defined categories and recording rules to classify behaviors they observe in a consistent way.
observation delusionnoun: Someone holds a firmly maintained false belief that other people are watching them, despite evidence against it.
observation holdnoun: A court requires a temporary hospital stay for evaluation, often to assess someone's ability to participate in legal proceedings.
observational learningphrase: Learning by watching others and copying what they do, whether in person or on video.
observational studynoun: Researchers record behavior or events as they occur without deliberately changing the conditions being studied.
observed variablephrase: A directly measured variable, such as a test score or answer, rather than an unseen trait.
observed-score equatingnoun: Statistical adjustments align score distributions across comparable test versions or administrations so results can be interpreted consistently.
observernoun: A person who carefully watches, notices, and records what happens during a test, study, or event.
observer biasphrase: A researcher's expectations can unintentionally change what they notice or record during an observational study.
observer driftnoun: Over time, an observer slowly and consistently changes how they score the same behaviors or events.
observer memorynoun: A personal event is remembered from an outside viewpoint, with the remembering person appearing within the scene.
observing responsenoun: An action reveals or clarifies a learned cue indicating whether another behavior is likely to receive reinforcement.
obsessionnoun: An unwanted, repeated thought, image, or urge that feels intrusive and causes strong anxiety or distress.
obsessional typenoun: Freud proposed a personality pattern dominated by conscience, with mental energy concentrated in the superego, the internal source of rules.
obsessive behaviornoun: Persistent doubt, repeated mental reviewing, or rigid ordering may occur in obsessive-compulsive disorder or obsessive-compulsive personality disorder.
obsessive-compulsive disorder (OCD)phrase: A disorder with unwanted thoughts and repeated acts done to reduce distress, often taking much time and disrupting life.
obsessive-compulsive personality disorderphrase: A personality pattern of extreme perfectionism, rigid control, and stubborn rule-following that harms flexibility and relationships.
obstetricsnoun: Medical care focused on pregnancy, childbirth, and the mother's health before and after birth.
obstruction methodnoun: Researchers estimate animals’ motivation by observing which goals they pursue and how readily they attempt to overcome barriers.
obstructive hydrocephalusnoun: Fluid builds up within the brain’s connected cavities because a blockage prevents its normal movement.
obstructive sleep apneanoun: Breathing repeatedly stops or decreases during sleep because the upper airway becomes partly or completely blocked.
obstruentnoun: A speech sound is produced when airflow briefly stops and then releases, as when saying p or b.
obtrusive ideanoun: An unwanted, persistent thought interrupts ordinary thinking and feels out of keeping with the person’s sense of self.
obturatornoun: A fitted device covers a gap in the roof of someone’s mouth and can help them produce clearer speech.
OCBabbreviation: Organizational citizenship behavior means voluntary employee actions that help a workplace beyond what the job formally demands.
Occam’s razornoun: When explanations fit the evidence equally well, this principle favors the one requiring fewer unsupported assumptions.
occasion setternoun: In conditioning, one cue signals whether another cue will predict an outcome.
occasion settingnoun: Learning establishes that one cue indicates when another cue will be followed by a particular outcome.
occasional causenoun: Within historical occasionalism, an apparent cause merely signals when God brings about the next event.
occasionalismnoun: This historical philosophy proposes that God produces events, including apparent interactions between mind and body, instead of events causing each other.
occipital cortexnoun: Back part of the brain's outer layer that mainly handles seeing.
occipital lobephrase: The back part of each brain hemisphere handles seeing, including color, shape, motion, and clear detail.
occlusionnoun: When one neuron branch fires with another, the combined response is smaller than adding each alone.
occultadjective: Something described this way involves hidden or mysterious knowledge, especially magical traditions or alleged supernatural phenomena.
occupationnoun: A group of jobs with similar tasks and needing similar skills, training, and personal qualities.
occupational abilitynoun: A person’s capacity to carry out tasks required for a particular kind of work can be assessed through tests.
occupational adjustmentnoun: The match between a worker’s skills, preferences, and personal traits and actual job demands, surroundings, and opportunities determines this fit.
occupational analysisnoun: Researchers systematically gather, organize, and interpret information about particular kinds of work.
occupational biomechanicsnoun: This field studies workers’ movements and physical forces during tasks to improve performance and reduce muscle and joint problems.
occupational counselingnoun: Frank Parsons’s historical guidance approach combined understanding oneself, learning about occupations, and reasoning carefully to choose suitable work.
occupational crampnoun: Involuntary muscle contractions interfere with a practiced work task, often involving the hand or arm and sometimes causing pain.
occupational culturenoun: People in a particular occupation often share characteristic ways of speaking, thinking, valuing things, and behaving.
occupational diseasenoun: An illness develops because of exposures or conditions connected with someone’s work.
occupational ergonomicsnoun: This field designs work tasks and systems to fit workers’ physical abilities, mental processes, and social and emotional needs.
occupational health psychologynoun: This branch of psychology examines how workplaces support or threaten workers’ health and applies findings to improve their well-being.
occupational interest measurenoun: A questionnaire compares someone’s preferred activities with workers’ interest patterns to suggest occupations they might enjoy.
occupational neurosisnoun: This historical label described work-related distress or difficulty working that was attributed to psychological conflict, sometimes overlooking medical causes.
occupational normnoun: A typical test score among people in one occupation provides a comparison point for assessing an individual’s results.
occupational psychologynoun: This branch of psychology studies people at work and applies findings to improve workplace effectiveness and employee well-being.
occupational rehabilitationnoun: Support, assessment, guidance, and training help people with disabilities, illness, or injuries enter employment or return to work.
Occupational Safety and Health Administration (OSHA)noun: This United States federal agency sets and enforces workplace standards intended to protect workers’ health and safety.
occupational segregationnoun: Workers from different social groups, such as genders or ethnicities, are concentrated in different occupations rather than distributed evenly.
occupational statusnoun: The social standing of an occupation depends on how much respect or prestige society gives its members.
occupational stressphrase: Stress reactions caused by unhealthy work demands or conditions that harm a person's body, mind, or well-being.
occupational testnoun: An assessment measures someone’s existing skills or potential to perform tasks in a particular occupation.
occupational therapy (OT)noun: Personalized activities, skill practice, and environmental changes help people participate in meaningful daily life and become more independent.
OCDabbreviation: A disorder with unwanted thoughts and repeated actions a person feels driven to do.
oceanic feelingnoun: A person feels their awareness extend beyond bodily limits, merging with the universe and sometimes bringing a sense of limitless power.
oceanic statenoun: Someone experiences their self as boundless, sometimes with intense connection, spiritual unity, or a feeling of knowing everything.
octavenoun: Two tones are separated by this musical interval when one vibrates at exactly twice the frequency of the other.
octave effectnoun: An animal’s learned response to a tone transfers more strongly to an octave-related tone than to some closer frequencies.
ocul-prefix: This word part means eye and appears in terms describing eyes or their functions.
ocularadjective: Connected with the eye or with the process of seeing.
ocular accommodationnoun: The eye adjusts its lens shape to bring objects at different distances into clear focus on the retina.
ocular apraxianoun: A person has difficulty deliberately starting or controlling eye movements, such as looking toward or following a target.
ocular dominancenoun: A neuron in the primary visual cortex responds more strongly to input from one eye than from the other.
ocular dominance columnnoun: A strip through the primary visual cortex contains neurons that mainly favor visual input from the same eye.
ocular dominance histogramnoun: A bar graph summarizes how strongly visual neurons favor input from one eye compared with input from the other.
ocular dysmetrianoun: Quick eye movements miss their intended target by stopping too soon or traveling too far.
ocular flutternoun: Both eyes make bursts of rapid, involuntary horizontal movements back and forth without normal pauses between them.
ocular hypertelorismnoun: The bony eye sockets are spaced farther apart than usual, sometimes as part of a genetic or developmental condition.
ocular myopathynoun: A muscle disorder affects the muscles responsible for moving the eyes.
ocular palsynoun: Weakness or paralysis of one or more muscles that move the eyes limits normal eye movement.
ocular pursuitnoun: The eyes move to keep a moving object in view and maintain their focus on it.
oculo- (ocul-)prefix: This combining form adds the meaning eye to words about eye structures, movements, or related functions.
oculocerebral-hypopigmentation syndromenoun: A rare inherited condition combines unusually little skin and hair pigment, eye differences, intellectual disability, and muscle stiffness.
oculocerebrorenal syndromenoun: A rare inherited condition, also called Lowe syndrome, affects eyes, kidneys, and development, mainly in boys.
oculogravic illusionnoun: An object seems to shift or tilt when the direction of apparent gravity changes.
oculogyral illusionnoun: A still, dim light seems to move during rotation because balance signals produce involuntary eye movements.
oculogyric crisisnoun: An involuntary eye muscle spasm holds the eyes in one direction for minutes or hours, sometimes after certain medications.
oculomotor apraxianoun: A neurological condition makes it difficult to start or control intentional eye movements.
oculomotor changesnoun: Changes in the visual surroundings produce adjustments in eye movements and related visually guided actions.
oculomotor nervenoun: The third cranial nerve controls most eye movements, raises the eyelid, helps focus the lens, and narrows the pupil.
oculomotor nucleusnoun: A cluster of brainstem nerve cells sends movement commands through the third cranial nerve to eye muscles.
oculomotor palsynoun: Weakness or paralysis of muscles that move the eyeball results from problems in muscles, nerve connections, or controlling nerves.
oculosympathetic paralysisnoun: Disrupted sympathetic nerve signals cause a drooping eyelid, smaller pupil, and sometimes reduced sweating on one facial side.
oculovestibular responsenoun: Automatic eye movements triggered by stimulation of the balance system help stabilize vision and can reveal brainstem function.
ODnoun: An amount of a drug so large that it can seriously harm or kill.
odd–even reliabilitynoun: This estimate checks test consistency by correlating totals for alternating questions and adjusting the result to represent the complete test.
oddity from samplenoun: A learning procedure rewards choosing an option that differs from an example shown earlier.
oddity problemnoun: A task tests an animal's ability to notice differences by requiring selection of an object unlike a target or alternatives.
oddsnoun: A ratio comparing how likely something is to happen versus not happen, often written like 3:2.
odds ratio (OR)phrase: Compares the odds of an outcome in one group to another to show effect size.
odornoun: A smell sensed when airborne chemicals stimulate the olfactory nerve, the nerve for smelling.
odor prismnoun: Henning's historical model arranges six proposed basic smell categories at a prism's corners to show relationships among odors.
odorantnoun: A substance that enters the air can stimulate smell receptors and create a smell experience.
odorant-binding proteinnoun: A protein attaches to smell molecules and can help carry them through mucus toward smell receptors.
odorimetrynoun: The sensitivity of a person's sense of smell is measured using controlled odor tests.
odorvectornoun: The vapor released by a smell-producing substance reaches smell receptors through the nostrils or from the mouth through the throat.
Odylenoun: Reichenbach proposed an unproven force supposedly radiating from living beings, crystals, and magnets.
oedipal conflictnoun: Freud proposed that children experience unconscious sexual feelings toward one parent and rivalry with the other.
oedipal phasenoun: Freud proposed a period around ages three to five when unconscious sexual feelings toward a parent and parental rivalry develop.
Oedipus complexphrase: A boy's sexual wishes for his mother and jealousy toward his father in Freud's theory.
OEPabbreviation: An olfactory evoked potential is a measurable electrical brain response triggered by a smell stimulus.
OFAabbreviation: The occipital face area is a region near the brain's back that helps process visual information about faces.
off cells (OFF cells)noun: Certain visual nerve cells become electrically more active when light decreases in the area they monitor.
off response (OFF response)noun: A visual nerve cell's electrical charge shifts toward activation when light decreases in the region driving that response.
off-center bipolar cellnoun: A retinal relay neuron is inhibited by central light and excited by surrounding light within its monitored area.
off-center ganglion cellnoun: A retinal output neuron sends fewer signals with central lighting and more with surrounding lighting within its monitored area.
off-center/on-surroundadjective: Describes a sensory arrangement where central stimulation reduces a neuron's activity while stimulation in a surrounding ring increases it.
off-labeladjective: Describes prescribing a medicine for a problem the FDA has not officially approved.
off-task behaviorphrase: Actions or thoughts that pull someone away from the activity they are supposed to be doing right then.
off-the-job trainingphrase: Employee training that happens away from the usual work area, often in a classroom or practice setting.
off-time life eventsnoun: Major experiences happen at ages or life stages that differ from a particular population's usual expectations.
officer selectionnoun: Military candidates are assessed and chosen for officer responsibilities using evidence about their abilities, qualifications, and suitability.
officer trainingnoun: Military education prepares officers to lead others and handle the responsibilities of their roles.
officer-assisted suicidenoun: A person intending to die deliberately provokes police into using lethal force against them.
offline groupnoun: Members gather in person and communicate through direct, traditional means rather than mainly through digital technology.
ogivenoun: A cumulative frequency graph shows how many observations fall at or below each value.
Ohm’s lawnoun: An auditory principle proposes that hearing can separate a complex sound into its component pure tones.
oikofugicadjective: Describes an urge to leave home to travel or wander elsewhere.
oikomanianoun: An older clinical label describes excessive preoccupation with family members accompanied by irritable, controlling behavior.
oikotropicadjective: Describes feeling homesick or longing for the familiar comfort of home.
OKRabbreviation: The optokinetic reflex automatically moves the eyes to follow passing visual patterns, helping maintain a stable view.
olannoun: A historically described syndrome in some Siberian populations involves apparently involuntary copying of other people's actions.
olanzapinenoun: A newer antipsychotic medicine used for schizophrenia and mania, often causing sleepiness and weight gain.
old-fashioned racismphrase: Open, direct racist beliefs that some racial groups are inferior and should stay separate.
old-oldadjective: Describes adults aged 75 through 84 in one commonly used classification of later life.
Older Adult Resources and Servicesnoun: A trained interviewer uses this questionnaire to assess older adults' mental and physical health, social support, finances, and daily functioning.
oldest oldnoun: An age category groups adults who are 85 or older in some classifications of later life.
Oleptronoun: A brand name identifies an extended-release form of trazodone, a medication used to treat depression.
olfactienoun: A historical odor-intensity unit represents a smell strength just above the level needed for detection.
olfactionnoun: The ability to detect smells when odor molecules activate receptors inside the nose.
olfactometernoun: A device controls how smell-producing substances are delivered to the nose during testing or research.
olfactometrynoun: Controlled testing measures how sensitively someone can detect smells.
olfactophilianoun: Sexual interest or arousal is linked to body smells, particularly odors from genital areas.
olfactoriumnoun: A specially controlled room lets researchers measure how well someone detects smells under carefully managed air conditions.
olfactory adaptationnoun: Continued exposure to a smell temporarily makes it harder to notice or makes it seem weaker.
olfactory areanoun: A region of brain tissue helps process information about smells.
olfactory brainnoun: This historical name groups brain structures once regarded mainly as a smell system, including parts with other functions.
olfactory bulbnoun: A small brain structure receives signals directly from nasal smell cells and begins processing them.
olfactory cellnoun: A sensory nerve cell inside the nose detects odor molecules and sends signals toward the brain.
olfactory ciliumnoun: A tiny, hairlike extension of a nasal smell cell carries sites that detect odor molecules.
olfactory cortexnoun: A brain area near the temporal lobe receives smell signals from the nose and helps identify odors.
olfactory cross-adaptationnoun: Becoming less sensitive to one smell can also reduce sensitivity to a different smell.
olfactory dysfunctionnoun: A disturbance in smelling changes odor sensitivity, alters how smells seem, or produces smells without an outside source.
olfactory encodingnoun: Neural activity turns smell information into internal representations that the brain can process and potentially remember.
olfactory epitheliumnoun: A specialized tissue layer high inside the nose contains sensory cells that detect odor molecules.
olfactory eroticismnoun: Smells can produce pleasurable feelings that include sexual interest or arousal.
olfactory evoked potential (OEP)noun: An electrical response measured in the brain follows stimulation by a smell.
olfactory hallucinationnoun: Someone experiences a smell even though no corresponding odor source is present.
olfactory mucosanoun: Specialized moist tissue high inside the nose contains smell receptors, supporting cells, mucus glands, and nerve fibers.
olfactory nervenoun: Bundles of sensory fibers carry smell information from nasal receptor cells to the brain's olfactory bulbs.
olfactory receptornoun: A specialized nasal nerve cell detects odor molecules and starts signals used for smelling.
olfactory reference syndromenoun: Persistent concern about emitting an offensive smell unnoticed by others causes serious distress and often repeated washing or checking.
olfactory sense organnoun: This name describes a nasal sensory cell that detects odor molecules and sends nerve signals.
olfactory stimulationnoun: Odor molecules dissolved in nasal mucus activate smell receptors on tiny extensions of sensory cells.
olfactory sulcusnoun: A shallow groove beneath each frontal brain lobe houses the olfactory bulb and tract.
olfactory systemnoun: Sensory cells, nerve pathways, brain regions, and their activity work together to detect odors and guide responses.
olfactory tractnoun: A bundle of nerve fibers carries processed smell signals from an olfactory bulb toward other brain regions.
olfactory transductionnoun: Smell receptor cells convert contact with odor molecules into electrical changes that begin neural signaling.
olfactory tuberclenoun: A small raised brain region near the olfactory tract contains cells and fibers involved in processing smells.
oligarchynoun: Political or organizational power rests with a small, privileged group of people.
oligo- (olig-)prefix: A word beginning adds the meaning of few, little, or an insufficient amount.
oligodendrocytenoun: A supporting cell in brain and spinal cord tissue produces myelin insulation around nerve fibers, helping signals travel faster.
oligodendrogliomanoun: A brain tumor contains abnormal cells resembling oligodendrocytes, the supporting cells that make nerve insulation.
oligohydramniosnoun: Too little amniotic fluid surrounds a developing fetus, sometimes restricting movement and affecting development.
oligospermianoun: Semen contains an unusually low concentration of sperm, which can reduce the chance of causing pregnancy.
olisbosnoun: An artificial object shaped like a penis is used for sexual pleasure.
olivary nucleusnoun: An olive-shaped brainstem cell cluster supports movement coordination or hearing, depending on whether it is inferior or superior.
Oliver–McFarlane syndromenoun: A rare disorder involves unusually long eyelashes, short stature, retinal deterioration, and possible delays in movement and intellectual development.
olivocochlear bundlenoun: Nerve fibers carry signals from the brainstem's superior olive back toward sensory structures in the inner ear.
olivopontocerebellar atrophynoun: Progressive nerve cell loss affects the inferior olives, pons, and cerebellum, often disrupting balance, coordinated movement, and speech.
ololiuquinoun: These vine seeds contain hallucinogenic substances and were traditionally used by Indigenous communities in Mexico for healing and religious ceremonies.
OLSabbreviation: Ordinary least squares fits a prediction model by minimizing the total squared gaps between observed and predicted values.
OLSATabbreviation: This abbreviation names the Otis–Lennon test of school ability, which assesses reasoning with words, pictures, shapes, and numbers.
ombudsmannoun: A designated person or service investigates complaints and helps resolve problems between individuals and an organization.
omega squarednoun: An effect-size statistic estimates the share of outcome variation associated with one or more predictors in a population.
omega-3 fatty acids (omega 3s)noun: These polyunsaturated fats help build cell membranes and support brain development and other body functions.
omennoun: An event is interpreted as a sign that something fortunate or unfortunate will happen later.
omission biasnoun: People tend to judge harmful inaction less harshly than an action that produces equally harmful results.
omission trainingnoun: Reinforcement is given when a selected behavior stays absent for a set interval, helping that behavior become less frequent.
omitted variable biasnoun: Leaving out a relevant variable systematically distorts a model's estimates when that variable affects relationships being studied.
omnibus testnoun: A statistical test checks several differences or relationships together to assess whether an overall pattern is statistically significant.
omnipotencenoun: In psychology, a person feels or believes their wishes or thoughts can control events beyond themselves.
omnipotent therapistnoun: In prestige-based suggestion, a therapist's perceived authority helps their suggestions influence symptoms, sometimes temporarily.
on cells (ON cells)noun: Certain visual neurons become more electrically active when light increases in the central area they respond to.
on response (ON response)phrase: A visual neuron fires more when light gets brighter in the center of its receptive field.
on-center bipolar cellnoun: A retinal relay neuron becomes more active with central light and less active with surrounding light.
on-center ganglion cellnoun: A retinal output neuron increases signals toward the brain with central light but reduces them with surrounding light.
on-center/off-surroundadjective: A sensory response pattern involves central stimulation increasing a neuron's activity while stimulation around that center decreases it.
on-the-job trainingnoun: Workers learn needed job skills at the workplace during normal work hours while doing or practicing tasks.
on-time life eventsnoun: Life milestones happen around the ages considered usual or expected within a particular population.
on–off cellnoun: A visual neuron becomes electrically more active both when light appears and when it disappears.
onanismnoun: An older label describes masturbation or withdrawal of the penis from the vagina before ejaculation during intercourse.
oncologynoun: A medical and research field studies tumors, especially cancer, and develops ways to prevent, understand, and treat them.
ondansetronnoun: A medicine blocks serotonin's action at 5-HT3 receptors to prevent or relieve nausea and vomiting.
one-factor analysis of variancenoun: A statistical method tests whether group averages differ across categories or conditions of one factor.
one-group pretest–posttest designnoun: Researchers measure one participant group before an intervention and afterward, without a separate comparison group.
one-parameter modelnoun: A test model predicts answer success from ability and question difficulty, with difficulty as the only varying question characteristic.
one-person psychologynoun: A psychoanalytic perspective centers the patient's inner mental life and treats the therapist as a largely objective observer.
one-sample t testnoun: A statistical test uses a sample's average, variability, and size to assess its difference from a specified population average.
one-sample testnoun: A statistical procedure checks whether data from one sample differ meaningfully from a specified population pattern or value.
one-shot case studynoun: Researchers observe one group once after an event or intervention, without an earlier measurement or separate comparison group.
one-sided messagenoun: A communication supports just one position on an issue without presenting arguments for opposing positions.
one-tailed hypothesisnoun: A research prediction specifies both an expected effect and its direction, such as higher scores or lower scores.
one-tailed testphrase: A statistical test that checks for an effect in only one predicted direction.
one-trial learningnoun: A skill is mastered following just one training attempt.
one-way analysis of covariancenoun: A statistical method compares group averages across one factor while adjusting for measured variables related to the outcome.
one-way analysis of variancephrase: A statistical test comparing three or more group averages to see whether one variable likely affects an outcome.
one-way designnoun: An experiment changes one factor to examine how its different levels affect a measured outcome.
one-word stagenoun: During early language development, children speak using single words that can communicate larger messages through context and gestures.
oneirismnoun: A person experiences a state resembling a dream while awake.
oneiro- (oneir-)prefix: This word part adds a meaning connected with dreams.
oneirodynianoun: Dreaming involves distressing experiences, including frightening dreams that may be described as nightmares.
oneiromancynoun: A divination practice interprets dreams as supposed clues to future events.
oneirophrenianoun: A historical clinical label describes a dreamlike condition involving hallucinations, confused awareness, and disturbed perception.
oniomanianoun: A person experiences compulsive urges to shop or spend, buying things without considering whether they are needed or useful.
online groupnoun: People belong to a group whose communication happens mainly or entirely through digital technology.
online self-help groupnoun: People regularly connect through the internet to exchange peer support for a difficulty they share.
online social networknoun: People form a web of social connections and interact through internet-based technologies.
online therapynoun: Psychological treatment takes place through internet communication, including video sessions or written messages.
onomatopoeianoun: Words are created or used to imitate sounds associated with what they describe, such as buzz or splash.
onset insomniaphrase: Trouble falling asleep at the start of the night, even when you have the chance to sleep.
onset of actionphrase: The time from taking a drug until its effects can first be noticed.
ontoanalysisnoun: An existential approach explores the deepest nature of existence through analysis of a person's experience.
ontogenetic fallacynoun: A reasoning error treats a commonly observed age-related change as an inevitable, natural part of aging.
ontogenetic psychologynoun: A field examines psychological changes connected with an individual's biological development across life.
ontogenynoun: An individual organism undergoes biological development throughout its life, beginning at fertilization and ending at death.
ontogeny of conscious experiencenoun: Conscious awareness emerges and develops as an individual organism grows.
ontological confrontationnoun: A person becomes sharply aware of their own mortality when events or memories break through usual ways of avoiding it.
ontologynoun: A philosophical field investigates existence, what kinds of things are real, and what existing means.
oocytenoun: An immature reproductive cell develops toward becoming a mature egg cell.
oogenesisnoun: Reproductive precursor cells develop and undergo specialized divisions to produce mature egg cells.
oophorectomynoun: A surgical procedure removes one ovary or both ovaries.
opaqueadjective: A material blocks light from passing through it, preventing a view through the material.
open adoptionnoun: An adoption permits some communication between a child's birth and adoptive families, potentially supporting ongoing relationships.
open call systemnoun: An animal's vocal communication system allows new calls or songs to be learned throughout its lifetime.
open class societynoun: A society allows or encourages people to move between social classes or levels of social standing.
open designnoun: A classroom or office layout uses few physical barriers to create shared, flexible spaces for learning or work.
open economynoun: In operant learning research, animals receive food or water during sessions plus additional supplies outside sessions regardless of behavior.
open groupnoun: An ongoing group allows additional members to join after its activities or therapy sessions have begun.
open head injurynoun: A head injury involves an opening or penetration through the skull.
open hospitalnoun: A psychiatric care facility keeps doors unlocked and avoids using physical restraints on patients.
open marriagenoun: A marriage allows each spouse to have sexual relationships with other people through mutual agreement.
open questionphrase: Asks for an answer in the person's own words instead of choosing from set options.
open shopnoun: A workplace allows people to hold jobs whether they choose to join a labor union or remain outside it.
open skillnoun: A movement skill requires adjustment because the surrounding conditions change from one performance to the next.
open societynoun: A society protects rights, permits disagreement, elects leaders, and uses law and public criticism to guide change.
open studynoun: A research project allows additional people to enroll while the investigation is already underway.
open systemphrase: A group or organization that exchanges information, people, or resources with its surroundings.
open system theorynoun: A theoretical view treats organizations as exchanging resources and products with their surroundings while being shaped by outside influences.
open wardnoun: A hospital unit leaves its doors unlocked so people can move through them without unlocking a barrier.
open wordnoun: In pivot grammar, a young child pairs a content word with a frequently repeated word during early two-word speech.
open-class wordsnoun: These words belong to language categories, including nouns and verbs, that readily gain newly created or borrowed members.
open-classroom designnoun: A classroom layout uses observations of students’ activities to create flexible, open spaces for informal learning and group work.
open-classroom methodnoun: A teaching approach gives students choices about learning while teachers guide their progress and support individual needs.
open-door hospitalnoun: A psychiatric hospital provides care with unlocked entrances and exits and without physically restraining its patients.
open-ended interviewnoun: An interview uses questions that invite people to explain their experiences or views in their own words.
open-field chambernoun: An enclosed research space allows animals to move about while researchers record exploration, movement, and bowel activity.
open-field testnoun: An animal research procedure measures movement and other reactions in an open enclosure, sometimes to study signs associated with anxiety.
open-label studynoun: A treatment study lets both participants and researchers know which treatment each participant receives.
open-loop systemnoun: A control system follows its instructions without using feedback about results to adjust its actions.
open-office designnoun: An office layout places work areas together in a broad shared space with few dividing walls or partitions.
opening techniquenoun: A therapist uses an initial approach to help a client feel comfortable and begin building trust.
openmindednessnoun: A personality tendency involves considering different ideas and being willing to reconsider beliefs instead of holding them rigidly.
openness to experiencephrase: A Big Five trait marked by curiosity, imagination, and interest in new ideas, art, and experiences.
operandumnoun: A device in an animal learning experiment automatically records a response when the animal acts on it.
operantnoun: A behavior class grouped by the same effect it has on the environment.
operant behaviorphrase: Actions that affect the environment and become more or less likely depending on what happens afterward.
operant chambernoun: A small lab box that automatically gives cues and records actions during learning by consequences.
operant conditioningphrase: Learning happens when consequences after an action make that action more or less likely.
operant conditioning chambernoun: A controlled research enclosure records freely occurring animal actions and delivers events, such as food, according to experimental rules.
operant conditioning therapynoun: A therapy approach changes behavior by adjusting what happens before actions and the consequences that follow them.
operant learningphrase: Behavior changes because its consequences, like rewards or penalties, make it happen more or less often.
operant levelnoun: The starting rate or likelihood of a behavior is measured before researchers arrange consequences to reinforce it.
operant paradigmnoun: An experimental setup makes a consequence depend on a behavior to study how that relationship affects future actions.
operant responsephrase: One behavior that belongs to a learned group of actions shaped by its consequences.
operationnoun: A logical mental action in Piaget's theory that can be reversed in thought and combined with others.
operation span (OSpan)noun: A working memory task asks people to remember words in sequence while also solving or checking math problems.
operational analysisnoun: An analysis examines decisions and tracks inputs and outputs through complex tasks, often using mathematics to improve effectiveness.
operational definitionnoun: A description specifies the exact procedures researchers will use to observe or measure something they want to study.
operational researchnoun: An analytical field uses mathematical models and simulations to understand complex situations and support more effective decisions.
operational sex rationoun: This measure compares the numbers of males ready to mate with females ready to mate at a particular time.
operational thoughtphrase: In Piaget's theory, logical thinking used in the concrete and formal stages of children's development.
operationalismnoun: A philosophical position holds that a scientific concept gets its meaning from the observable procedure used to measure it.
operationismnoun: A philosophical view ties the meaning of scientific concepts to the specific observable operations used to establish them.
operationist view of consciousnessnoun: A historical proposal treats conscious experiences as reducible to events others can observe, such as a person distinguishing between stimuli.
operations researchnoun: A field applies mathematical analysis, models, and simulations to compare options and improve decisions in complex systems.
operative knowledgenoun: In Piaget’s theory, understanding develops through performing mental operations that transform information, rather than simply remembering facts or appearances.
operatorsnoun: Mental steps for knowing which actions change an amount and which only rearrange it.
ophidiophilianoun: An uncommon historical label describes a fascination with snakes regarded as unusually intense.
ophidiophobianoun: A specific phobia involves lasting, excessive fear of snakes that goes beyond the danger they actually present.
ophthalmianoun: A medical condition involves severe inflammation affecting the eye’s surface lining or structures located deeper inside.
ophthalmic nervenoun: A trigeminal nerve branch carries sensory information from the eye region, forehead, and parts of the nose.
ophthalmologynoun: A medical specialty studies eyes and provides diagnosis and treatment for eye diseases.
ophthalmometernoun: An eye examination instrument measures the cornea’s curvature, helping clinicians assess uneven curvature associated with astigmatism.
ophthalmoplegianoun: A condition causes paralysis in muscles that move the eyes or control structures inside them.
ophthalmoplegia externanoun: Paralysis affects the muscles that move the eyeballs, while the muscles controlling pupil size may remain functional.
ophthalmoscopenoun: A handheld examination instrument lets a clinician inspect internal eye structures, particularly the retina at the back.
opiatenoun: A substance comes from opium or a chemical modification of its compounds, with examples including morphine, codeine, and heroin.
opinionnoun: A personal belief or judgment about something, often shaped by feelings and experience.
opinion leadernoun: A socially connected person influences others because they seek that person’s advice or follow their example.
opinion surveynoun: A research method gathers many people’s views on a topic, sometimes using their answers to estimate a wider population’s views.
opinion testimonyphrase: In court, expert witnesses may share informed conclusions, not just what they directly saw or heard.
opinionnairenoun: A questionnaire measures someone’s beliefs or attitudes by asking them to accept or reject statements about particular topics.
opioidnoun: A class of drugs and natural brain chemicals that reduce pain and can also slow breathing and cause dependence.
opioid abusephrase: An older DSM diagnosis for harmful repeated opioid use causing serious life problems, unless dependence was diagnosed instead.
opioid agonistnoun: A drug activates opioid receptors in the nervous system, producing effects that can include pain relief and changes in mood.
opioid analgesicnoun: A pain medicine activates opioid receptors to reduce painful sensations and the distress they cause.
opioid antagonistnoun: A substance occupies opioid receptors and blocks or reduces the effects of drugs that activate them.
opioid blockadenoun: Medication reduces the rewarding high from other opioids as part of treatment for opioid use disorder.
opioid dependencephrase: A compulsive pattern of opioid use despite harm, often with tolerance or withdrawal when stopping.
opioid intoxicationphrase: Recent opioid use causing major behavior changes and body slowing, often with tiny pupils and sleepiness.
opioid neurotransmitternoun: A chemical messenger made within the body activates opioid receptors, helping regulate pain, reward, and other functions.
opioid receptornoun: A protein on a cell receives opioid molecules and uses internal signaling proteins to change the cell’s activity.
opioid systemphrase: A network of mu, kappa, and delta receptors helps control pain and reward in the brain and gut.
opioid use disorderphrase: A harmful pattern of opioid drug use marked by craving, tolerance, withdrawal, and continued use despite serious problems.
opioid withdrawalphrase: After heavy opioid use stops or drops, a person can develop distressing body and mood symptoms.
Opitz G/BBB syndromenoun: A genetic condition affects structures along the body’s center line and sometimes involves learning or intellectual difficulties.
opiumnoun: A dried substance from immature poppy seedpods contains morphine and other chemicals that can relieve pain and cause dependence.
opponent cellnoun: A visual neuron responds in opposing ways to contrasting inputs, such as red and green light in different viewing areas.
opponent process theory of acquired motivationnoun: A theory proposes that experiences trigger opposing emotions, with the slower opposite response strengthening through repetition and outlasting the initial feeling.
opponent process theory of color visionnoun: A theory explains visual experience through opposing signals organized into red–green, blue–yellow, and light–dark channels.
opportunismnoun: An organism can adjust to environmental changes by making use of newly accessible foods or other resources.
opportunity classnoun: A specialized class offers teaching and support suited to students whose learning or developmental needs require a different approach.
opportunity samplingnoun: Researchers choose participants or cases because they are easy to reach, rather than through a planned random selection.
opportunity structurenoun: A pattern of social conditions shapes which life options people can access given their circumstances and personal characteristics.
opposites testnoun: An assessment asks a person to give a word meaning the reverse of each word presented.
oppositional defiant disorderphrase: A childhood disorder marked by at least 6 months of angry, defiant behavior toward adults without serious rule-breaking.
opsinnoun: A light-sensitive protein in eye cells that helps rods and cones detect different wavelengths.
opt-prefix: This word-building form adds a meaning connected with eyesight or the eyes to a larger word.
optic aphasianoun: A naming difficulty prevents someone from saying an object’s name when they see it, despite potentially recognizing it.
optic apraxianoun: A difficulty linking seen objects with their proper actions disrupts tool selection, object use, or the order of tasks.
optic arraynoun: The pattern of light available at a viewing position carries information about surrounding objects and surfaces.
optic ataxianoun: A difficulty using sight to guide the hand causes inaccurate reaching toward objects, often following parietal brain damage.
optic atrophynoun: Nerve fibers carrying visual signals from the eye deteriorate, which can reduce a person’s vision.
optic chiasmnoun: A junction beneath the brain lets some visual nerve fibers cross, routing information from each eye to both brain halves.
optic disknoun: A small retinal area where nerve fibers exit the eye lacks light detectors, creating a gap in vision.
optic flownoun: The changing pattern of images across the retina provides clues about movement of the observer and surrounding objects.
optic nervenoun: A bundle of retinal nerve fibers carries visual signals from an eye toward the brain’s optic chiasm.
optic neuritisnoun: Inflammation affects the nerve carrying visual signals from an eye and can cause pain and sudden vision loss.
optic radiationsphrase: Bundles of vision nerve fibers carry signals from the thalamus to the visual cortex and pupil-control areas.
optic tectumnoun: A midbrain region processes visual information and helps direct the eyes and head toward things in the environment.
optic tractnoun: A nerve-fiber bundle carries visual information beyond the optic chiasm toward processing centers in the thalamus and midbrain.
optical axisnoun: An imaginary reference line runs through an optical system’s center, passing through the cornea and lens in an eye.
optical defectnoun: An eye condition prevents incoming light from forming a sharp image on the retina, making vision less clear.
optical flow patternnoun: A pattern of visual change across the retina signals how the observer and nearby objects are moving relative to one another.
optical illusionnoun: A visual experience makes something appear different from its physical properties because of light conditions or perceptual processing.
optical projectionnoun: A perceptual process places objects in surrounding space according to the images they form on the retina.
optical scannernoun: A device uses light to examine material or convert pictures and printed information into computer data.
opticiannoun: A trained worker makes, fits, or supplies eyeglass lenses and frames based on a vision prescription.
opticsnoun: A branch of physics studies light, its behavior, and how it contributes to vision and image formation.
optimal adjustmentnoun: The best achievable way of coping supports a person in managing daily life or a particular stressful situation.
optimal apparent motionnoun: An illusion of movement appears most convincing when visual displays have the best timing, spacing, and other suitable conditions.
optimal arousal theorynoun: A motivational theory proposes that people adjust their exposure to stimulation to reach and sustain their desired degree of excitement or alertness.
optimal designnoun: An experimental approach selects study conditions and participant assignments to best meet specific statistical goals.
optimal distinctiveness theorynoun: A theory proposes that people seek a balance between belonging with others and maintaining a distinct identity.
optimal foraging theorynoun: A theory predicts that evolution favors feeding patterns that maximize nutritional gains relative to search and handling costs.
optimal functioningnoun: A person’s best possible performance and well-being extend across areas such as relationships, school, work, and everyday life.
optimal levelnoun: In skill theory, the most complex performance someone can manage becomes possible when environmental support is at its strongest.
optimal outbreedingnoun: A proposed mating pattern favors partners genetically different enough to avoid close inbreeding, but not extremely different.
optimal scalingnoun: A statistical method assigns numerical scores to categories to reveal relationships and patterns that may otherwise be difficult to detect.
optimal stimulation principlenoun: A learning theory proposes that organisms learn actions that bring stimulation closer to a level they prefer.
optimismnoun: A hopeful expectation that good outcomes are likely and goals can be reached.
optimizationnoun: Using math rules on sample data to find the most accurate estimate for a population value.
optimizeverb: To improve conditions so the best possible result happens, even with limits.
opto- (opt-)prefix: This combining form builds words whose meanings involve eyesight, the eyes, or processes connected with seeing.
optogramnoun: A physical pattern forms on the retina when light changes the pigment rhodopsin, leaving differently bleached areas.
optokinetic effectnoun: A response involves eye movements triggered by moving sights, or changes in perception and movement associated with the eyes moving.
optokinetic reflex (OKR)noun: Automatic eye movements follow a moving scene and repeatedly reset, helping keep vision steady.
optometrynoun: A healthcare field examines vision and eye health and provides care such as corrective lenses.
ORabbreviation: A number showing how much more likely one outcome is in one group than another.
or rulephrase: Adds the chances of two events when you want the chance that either one happens.
or-prefix: Used at the start of a word to mean mouth or related to the mouth.
ora serratanoun: The jagged front boundary of the light-sensitive retina lies next to the eye's ciliary body.
oral administrationnoun: Medicine enters the body through the mouth, usually by being swallowed into the digestive system.
oral behaviornoun: Actions that involve the mouth include eating, speaking, sucking, and kissing.
oral characternoun: Historical psychoanalysis proposed that lasting personality patterns arise when development remains tied to early experiences of sucking and biting.
oral coitusnoun: This sexual activity involves using the mouth to stimulate a penis.
oral contraceptivenoun: A hormone-containing pill taken on a schedule helps prevent pregnancy by changing reproductive processes.
oral eroticismnoun: Psychoanalytic theory describes pleasure centered on mouth activities, including sucking, chewing, and kissing.
oral gratificationnoun: Within psychoanalytic theory, satisfaction can come from mouth activities such as sucking, chewing, or kissing.
oral historynoun: A person's spoken account of their past, usually gathered through an interview, provides information about experiences and perspectives.
oral methodnoun: This educational approach emphasizes speech, lipreading, and available hearing for deaf people, while discouraging or excluding signing.
oral personalitynoun: An older psychoanalytic theory links adult personality traits to becoming stuck in a developmental period centered on mouth experiences.
oral phasenoun: Freud proposed an initial developmental period, mainly during infancy, when pleasure centers on sucking and other mouth activities.
oral sadismnoun: Historical psychoanalysis proposed an urge, originating in infant biting, to use mouth actions for aggression, control, or cruel sexual pleasure.
oral sexnoun: Sexual activity in which someone's mouth stimulates another person's external genitals is called oral sex.
oral soundnoun: A speech sound is produced with air passing mainly through the mouth rather than the nose.
oral stagephrase: Freud's first psychosexual stage, from birth to about age one, centers pleasure and comfort on the mouth.
oral-aggressive personalitynoun: Historical psychoanalysis proposed that unsatisfying early sucking and biting experiences could produce a hostile, critical, or envious personality.
oral-biting phasenoun: Historical psychoanalysis proposed a later mouth-centered period when infant biting expresses growing independence and mixed feelings toward the mother.
oral-receptive personalitynoun: Historical psychoanalysis proposed that satisfying early sucking and maternal attention encourage friendliness, optimism, generosity, and comfort depending on others.
oral-sadistic phasenoun: An older psychoanalytic theory describes a period when infant biting supposedly expresses independence, hostility, and mixed feelings about the mother.
oral-sucking phasenoun: Historical psychoanalysis proposed an early infant period when sucking brings pleasure and a fantasy of taking the mother inside oneself.
oral–genital contactnoun: This sexual activity involves contact by mouth or tongue to stimulate genitals.
oral–lingual dyskinesianoun: A movement disorder causes uncontrolled tongue, mouth, and facial movements and can be associated with older antipsychotic medicines.
oral–motor feeding problemnoun: Difficulty controlling feeding muscles severely disrupts sucking or swallowing, often in children born prematurely or with movement disorders.
Oraletnoun: This brand name identifies an oral form of fentanyl, a powerful opioid medicine used in medical care.
oralismnoun: An approach to educating deaf people prioritizes speaking, lipreading, and usable hearing while limiting or excluding sign language.
oralitynoun: Psychoanalytic theory assigns mouth-related pleasure and habits a role in emotional life and psychological difficulties.
Orapnoun: This brand name identifies pimozide, an antipsychotic medicine also used to manage severe tics associated with Tourette syndrome.
Orbison illusionnoun: A shape appears bent or otherwise distorted because of a surrounding pattern of repeated lines.
orbitofrontal cortexnoun: A brain area under the frontal lobes helps control impulses, emotion, and reward-based decisions.
orchidectomynoun: A surgical procedure removes one or both testicles, often to treat disease or injury.
ordernoun: A level in classifying living things that groups together related families within a larger class.
order effectphrase: Responses change because the same person gets conditions in a certain sequence, not because the conditions truly differ.
order of magnitudenoun: A number's rough size is described using powers of ten, with each step representing a tenfold change.
ordered scalenoun: A measurement system ranks values without showing how large the gaps between those ranks are.
orderlinessnoun: A habit of keeping things neat, organized, and in their proper places.
ordinaladjective: Describing data that can be put in order or rank, without assuming equal gaps between levels.
ordinal dataphrase: Numbers that show order or rank, but not equal gaps between scores, are used to sort results.
ordinal scalephrase: Ranks things in order without showing how far apart the ranks are.
ordinal variablenoun: A measured characteristic has values that can be ranked, but their spacing does not show exact differences.
ordinalitynoun: An understanding of relative amounts lets someone recognize when one quantity is greater or smaller than another.
ordinary creativitynoun: People use flexible, original thinking to find fresh ideas and solutions in everyday activities.
ordinary least squares regressionphrase: A method for drawing the best straight-line prediction by making squared prediction errors as small as possible.
ordinatenoun: A point's vertical coordinate gives its position along the y direction on a graph.
Orestes complexnoun: Historical psychoanalytic theory proposed that a son might push a wish for his mother's death outside conscious awareness.
orexinnoun: A brain signaling peptide made in the hypothalamus helps regulate wakefulness and feeding, with deficiency linked to some narcolepsy.
orexisnoun: The emotional and desire-driven side of an activity involves feelings and wants rather than its thinking processes.
organ inferioritynoun: In Adler's theory, someone feels inadequate because they view an actual or imagined bodily difference as a personal shortcoming.
organ languagenoun: Historical psychoanalysis proposed that physical symptoms symbolically express emotional conflicts, with the affected body part carrying personal meaning.
organ of Cortinoun: A structure inside the cochlea contains sensory hair cells that convert sound vibrations into signals for hearing.
organ speechnoun: An older psychoanalytic idea treats bodily symptoms as symbolic expressions of emotional struggles connected to the affected organ.
organ transplantationnoun: Surgery places an organ into a new location or another person's body, usually to replace an organ that cannot function adequately.
organellenoun: A specialized structure within a cell performs a particular job, often inside its own surrounding membrane.
organicadjective: Describes symptoms caused by physical changes in body organs or tissues, not mainly by psychological factors.
organic amnesianoun: Physical illness or damage affecting brain function can leave someone unable to remember some information or experiences.
organic approachnoun: This viewpoint explains every mental disorder through physical alterations affecting the brain or organs elsewhere in the body.
organic defectnoun: In this usage, a condition present at birth results from influences during pregnancy rather than a genetic change.
organic disordernoun: A health condition results from an identifiable change in the structure or chemistry of bodily tissues or organs.
organic hallucinationsnoun: Sensory experiences without an outside source can result from identifiable brain conditions, medications, or other substances.
organic paralysisnoun: Damage to nerves or muscles prevents a person from deliberately moving affected body parts.
organic retardationnoun: An organ develops more slowly or incompletely because of genetic differences, missing nutrients, or hormone problems.
organic selectionnoun: Learning may shape evolution by helping organisms survive and favoring inherited traits that support useful behavior.
organic sensationnoun: A feeling comes from activity inside the body, such as fullness or movement in the stomach.
organic therapiesnoun: Physical treatments address mental disorders through methods such as medication, electrically induced seizures under anesthesia, or selected brain surgery.
organic variablenoun: An internal condition or process helps determine how an organism reacts to something happening around it.
organicismnoun: According to this theory, every mental disorder arises from physical changes in the brain or other organs.
organicitynoun: An older clinical label grouped together conditions involving injured brain tissue or disturbed brain functioning.
organicity testnoun: This outdated label described a thinking or behavior assessment sensitive to problems caused by brain injury or dysfunction.
organismnoun: A living thing, such as a plant, animal, or bacterium, that can grow and reproduce.
organismicadjective: Describing parts that work together in a living thing to keep the whole body functioning smoothly.
organismic modelnoun: Development follows patterns shaped by interactions among an organism's parts, including its biological growth and its own actions.
organismic personality theorynoun: Personality is understood through the coordinated activity of the entire person, with bodily and mental processes working together.
organismic psychologynoun: This approach studies people as unified living beings whose mental and bodily activities interact with their surroundings.
organismic valuing processnoun: Rogers's theory proposes an inborn ability to sense which experiences support personal growth and fulfillment.
organismic variablenoun: In SORC behavioral assessment, a person's bodily and psychological characteristics help explain their actions in a situation.
organizationnoun: A company or other structured workplace where different parts work together to meet shared goals.
organizational approachnoun: This emotion framework explains how feelings coordinate thoughts, perceptions, motives, and actions to guide adaptation and relationships.
organizational assessmentphrase: Evaluating a workplace's structure, culture, and routines to understand employee morale, productivity, and how well the organization works.
organizational attractivenessnoun: A workplace's perceived appeal influences whether people want to apply, accept an offer, or continue working there.
organizational behavior management (OBM)noun: Applied behavior analysis improves workplace practices through changes such as clearer instructions, training, feedback, and rewards.
organizational careernoun: A person builds a career within one organization, expecting continued employment and gradual advancement in exchange for lasting commitment.
organizational citizenship behavior (OCB)noun: An employee voluntarily helps their workplace through actions beyond what their job formally requires.
organizational climatephrase: Workers' shared sense of what their workplace feels like day to day.
organizational commitmentphrase: An employee's loyalty to a workplace and desire to keep being part of it.
organizational culturephrase: The shared values, habits, and ways of thinking that shape how people act in a workplace.
organizational culture analysisnoun: Managers and employees examine shared workplace habits and beliefs to identify what supports or obstructs the organization's goals.
organizational development (OD)phrase: Planned efforts help a workplace work better by improving its structure, climate, and how people handle change.
organizational dynamicsnoun: Interacting forces and activities within an organization shape how it grows, develops, and changes over time.
organizational effectnoun: Hormone activity during early development can produce lasting changes in brain function and later behavior.
organizational effectivenessnoun: An organization's success can be judged by its goals, adaptability, continued operation, and ability to meet important groups' expectations.
organizational efficiencyphrase: Getting the most useful work from people and resources with the least waste of time, effort, or money.
organizational hierarchynoun: Workplace positions form ranked levels that assign decision-making power, responsibility, and reporting relationships.
organizational hypothesisnoun: This hypothesis proposes that hormones from developing testes shape the brain early, producing lasting effects on behavior typical of males.
organizational identificationnoun: An employee experiences membership in their workplace as part of who they are.
organizational justicephrase: Workers' sense that their workplace is fair in rewards and in how decisions are made.
organizational politicsnoun: People use influence within a workplace to advance their own interests or their department's interests over those of others.
organizational psychologyphrase: Studies how workplace systems, leadership, and groups affect employees' behavior, motivation, and job satisfaction.
organizational structurenoun: How an organization arranges jobs, authority, and communication among its different parts and people.
organized offendernoun: In a disputed criminal profiling classification, a person is described as carefully planning crimes rather than acting impulsively.
organogenesisnoun: During early development, body organs form from simpler tissues and start taking shape.
organum vasculosum of the lamina terminalis (OVLT)noun: A small brain structure monitors blood contents through unusually permeable blood vessels and helps regulate thirst and fluid balance.
orgasmnoun: The peak of sexual pleasure brings a release of tension and repeated muscle tightening in the pelvis.
orgasmic dysfunctionnoun: A person has persistent difficulty reaching orgasm, either generally or in particular circumstances.
orgasmic phasenoun: In a traditional sexual response model, this stage involves orgasm, a brief peak of sexual pleasure and bodily release.
orgasmic platformnoun: Tissue near the vaginal opening and inner labia swells with blood during sexual arousal.
orgasmic reconditioningphrase: A behavior therapy that tries to shift sexual arousal from harmful targets to safer ones during masturbation.
orgastic potencynoun: Wilhelm Reich used this concept for a person's ability to experience what he considered a full orgasm during sex.
orgonenoun: Wilhelm Reich proposed an unproven universal energy that he believed powered life, creativity, and sexual functioning.
orgone therapynoun: Reich's historical treatment linked psychological well-being to complete orgasm and an unproven energy he called orgone.
orgynoun: A social gathering involves several people taking part in sexual activity together, sometimes alongside other celebrations.
oriental nightmare-death syndromenoun: This outdated label describes bangungut, reports of unexpected death during sleep, sometimes with apparent nightmare distress, particularly among Filipino men.
orientationnoun: A planned introduction that helps a newcomer learn the rules, people, and routines of a job or school.
orientation and mobility training (O＆M training)noun: Specialized instruction helps blind people and people with low vision locate themselves and travel safely using senses, skills, and aids.
orientation columnnoun: A narrow grouping of neurons across primary visual cortex layers responds most strongly to edges at a similar angle.
orientation illusionnoun: When consciousness is impaired, someone may incorrectly recognize places, people, or other things around them.
orienting responsenoun: Attention, movement, and bodily activity shift toward something new, changed, or unexpected in the surroundings.
origin-of-language theorynoun: An explanation proposes how language first emerged and developed during the history of the human species.
original causenoun: The earliest or primary event in a causal sequence starts the process leading to a particular outcome.
original sinnoun: In Christian theology, humanity is understood as inheriting a sinful condition associated with Adam and Eve's first disobedience.
originalitynoun: The ability to come up with ideas that are new, unusual, and useful.
Orne effectnoun: Study participants may guess what a researcher wants and adjust their behavior to fit those expectations.
ornithinemianoun: The blood contains an unusually high amount of ornithine, an amino acid, sometimes because of inherited metabolism problems or liver disease.
oro- (or-)prefix: This word part means mouth and appears at the beginning of medical and anatomical terms.
orofacial apraxianoun: A person struggles to deliberately perform learned mouth or facial movements despite understanding the task and having sufficient muscle strength.
orofacial dyskinesianoun: Unwanted movements affect the mouth, face, or tongue, including repeated chewing motions or tongue movements.
orogenital activitynoun: Sexual contact involves using the lips or tongue to stimulate another person's genitals.
oropharynxnoun: The middle section of the throat lies behind the mouth and provides a passage for both food and air.
orphanin FQnoun: A naturally produced brain peptide, also called nociceptin, influences pain signaling through its own receptor within the opioid receptor family.
orphenadrinenoun: An acetylcholine-blocking medicine relieves muscle spasms and can treat movement problems caused by some antipsychotic medicines.
Ortgeistnoun: A place's physical surroundings and local culture help shape its social life, economy, and artistic expression.
orthergasianoun: A historical concept describes mental activity and mind-body functioning considered normal within Adolf Meyer's framework.
ortho- (orth-)prefix: This word-building element adds the meaning of straight, at right angles, correct, or corrective to another word.
Ortho-Raternoun: A portable screening instrument quickly checks how clearly someone sees, distinguishes colors, and judges depth.
orthodox psychoanalysisnoun: A traditional Freudian therapy uses freely shared thoughts, dream interpretation, and exploration of resistance to build insight into unconscious life.
orthodox sleepnoun: An older name describes nonrapid eye movement sleep, which includes both lighter sleep and deeper, slow-wave sleep.
orthogenesisnoun: A historical theory proposed that evolution follows an internally fixed direction rather than being guided by natural selection.
orthogenetic principlenoun: Heinz Werner proposed that development moves from undivided functioning toward distinct abilities organized into increasingly coordinated systems.
orthogonaladjective: Describes variables or study factors arranged independently, often shown as axes meeting at right angles.
orthogonal codingnoun: Researchers assign numerical weights to groups so planned comparisons capture separate, nonoverlapping information under appropriate statistical conditions.
orthogonal contrastnoun: A comparison of group averages is constructed to capture information that does not overlap with specified other comparisons.
orthogonal designnoun: An experiment combines every setting of its factors with balanced or proportional observations, allowing their effects to be separated statistically.
orthogonal rotationnoun: A factor analysis method makes hidden patterns easier to interpret while keeping the resulting factors uncorrelated.
orthographic distinctiveness effectnoun: People tend to remember words containing unusual letter patterns better than words containing more familiar patterns.
orthographynoun: A language's writing system includes the accepted ways its words are spelled and represented with written symbols.
orthokinesisnoun: An organism changes how fast or how often it moves in response to changes in stimulation.
orthomolecular medicinenoun: An alternative approach uses nutrients, often in very high doses, to address proposed biochemical imbalances, with uncertain effectiveness.
orthonasal olfactionnoun: Smell occurs when odor molecules enter through the nostrils and reach the nose's smell receptors.
orthopedic canenoun: A sturdy walking aid supports some body weight and helps people with movement difficulties maintain balance.
orthopsychiatrynoun: Professionals from health, education, and social fields work together to prevent mental health problems and provide early treatment.
orthopticsnoun: A clinical field assesses and treats difficulties coordinating the eyes so they can work together effectively.
orthoptoscopenoun: An eye-testing instrument measures eye misalignment and assesses how well the eyes can combine their views.
orthorexia nervosanoun: A proposed condition involves rigid concern about supposedly healthy eating that disrupts daily life or compromises nutrition.
orthostatic hypotensionnoun: A sudden blood pressure drop on standing up can cause dizziness, fainting, and falls, often as a medication side effect.
orthoticsnoun: A medical specialty fits and uses braces and similar devices to support, align, or improve body movement.
oscillator circuitnoun: A connected system generates an output pattern that repeats, whether in an electronic device or a biological network.
oscillatory interference modelnoun: A proposed explanation suggests interacting rhythms of brain activity create the repeating spatial firing patterns of grid cells.
oscillographnoun: An instrument draws a lasting record of changing electrical signals, including signals measured during studies of bodily activity.
oscillometernoun: An instrument measures repeated fluctuations, especially changes associated with bodily processes such as the arterial pulse.
oscillopsianoun: A person experiences stationary surroundings as if they were shaking, bouncing, or moving back and forth.
oscilloscopenoun: An electronic instrument displays changing electrical signals as wave-shaped traces that can be inspected on a screen.
OSHAabbreviation: This U.S. federal agency creates and enforces rules to help keep workplaces safe and protect workers’ health.
osmolagnianoun: Sexual interest or pleasure is associated with body odors, particularly smells from the genital area.
osmolaritynoun: The concentration of dissolved particles that contribute to osmosis is expressed in osmoles for each liter of solution.
osmometernoun: An instrument measures osmotic pressure or estimates the concentration of particles dissolved in a liquid.
osmometric thirstnoun: The urge to drink develops when concentrated surrounding body fluids draw water from cells, leaving them dehydrated.
osmoreceptornoun: A specialized sensory cell detects changes in body fluid concentration and helps regulate thirst and release of water-conserving hormones.
osmoregulationnoun: The body adjusts water and dissolved salts to keep fluids inside and outside cells within suitable ranges.
osmosisnoun: Water or another solvent moves through a selective membrane toward the side with a higher concentration of dissolved particles.
osmotic pressurenoun: The pressure needed to stop net solvent movement across a selective membrane depends on differences in dissolved particle concentration.
OSpanabbreviation: The operation span task measures working memory by asking people to remember items in order while completing arithmetic problems.
osphresiolagnianoun: Sexual excitement or erotic feelings arise in response to particular smells.
osphresiophilianoun: A historical label describes an unusually strong attraction to smells.
osseous labyrinthnoun: Bony spaces within the skull surround the inner ear's delicate structures involved in hearing and balance.
ossiclesnoun: Three tiny middle-ear bones pass sound vibrations from the eardrum toward the inner ear, helping hearing work efficiently.
osteomalacianoun: Adult bones become soft because they do not gain enough minerals, commonly because of insufficient vitamin D.
osteopathynoun: A healthcare approach emphasizes the whole person and connections between body structure and function, sometimes using hands-on muscle and joint treatment.
osteopetrosisnoun: A rare inherited condition disrupts bone breakdown and renewal, producing unusually dense bones that can still break easily.
osteoporosisnoun: A disease in which bones lose density, making them weak and easier to break.
ostracismnoun: People experience this form of social rejection when others leave them out and act as though they are absent.
Ostwald color systemnoun: This color arrangement places 24 hues around a circle, with complementary pairs opposite each other, and also organizes neutral shades.
OTabbreviation: Occupational therapy helps people build independence and support health through meaningful everyday activities and changes to their surroundings.
ot-prefix: This word part means ear and appears in words about ear structures, conditions, or care.
OTCabbreviation: Over-the-counter describes medicines that people can buy without getting a prescription from a medical professional.
Othello syndromenoun: A person firmly believes their partner is being unfaithful despite evidence that does not support this belief.
other-directedadjective: Guided mainly by group expectations, goals, and values instead of personally chosen standards.
other–total ratio (OTR)noun: This ratio divides outsiders to a person's subgroup by everyone present, with larger values proposed to predict greater self-focused attention.
oticadjective: This adjective describes something connected with the ear, including its structures, conditions, or treatments.
Otis–Lennon School Ability Test (OLSAT)noun: This multiple-choice test measures students' reasoning with words, pictures, shapes, and numbers to help predict school performance.
otitis medianoun: Inflammation behind the eardrum, sometimes involving infection or fluid, can temporarily reduce how well sound travels through the ear.
oto- (ot-)prefix: This combining word part means ear and helps form words about hearing, ear anatomy, and related conditions.
otoacoustic emissions (OAEs)noun: The cochlea generates faint sounds, spontaneously or after stimulation, that microphones can detect to help assess its function.
otoconiumnoun: A tiny calcium-containing crystal sits in gel within an inner-ear balance organ, helping detect gravity and straight-line movement.
otohemineurasthenianoun: This historical label describes hearing loss affecting one ear when no physical cause can be identified.
otolaryngologynoun: This medical specialty evaluates and treats conditions involving ears, nasal passages, the throat, and nearby head and neck structures.
otolithnoun: A small calcium-containing particle in the inner ear's balance sacs helps the body sense head tilt and straight-line acceleration.
otologynoun: This branch of medicine studies ear function and identifies and treats conditions affecting the ear.
otoneurologynoun: This field studies how hearing relates to the nervous system, including the nerve processes involved in hearing.
otopalatodigital spectrum disordersnoun: Changes to the FLNA gene cause this family of genetic conditions affecting skeletal growth, hearing, and palate formation.
otosclerosisnoun: Unusual bone growth around inner-ear structures can restrict the stapes bone's movement and gradually reduce hearing.
ototoxicadjective: A substance or exposure with this property can damage ear structures involved in hearing or balance.
OTRabbreviation: The other–total ratio divides people outside a target subgroup by everyone present and is proposed to predict self-focused attention.
ought selfnoun: Your mental picture of who you should be reflects qualities you believe your duties or social expectations require.
Ouija boardnoun: Participants touch a movable pointer on a lettered board to produce messages sometimes attributed to spirits, without establishing spirit involvement.
out-of-body experiencenoun: A person feels as though their awareness is outside their physical body, sometimes seeming to observe it from elsewhere.
outbreedingnoun: Reproduction occurs between individuals who are unrelated or only distantly related, generally within the same species.
outcomenoun: The result or reward that comes from a treatment, program, action, or interaction.
outcome dependencenoun: What happens to one person depends partly or entirely on what another person does.
outcome evaluationphrase: Checking whether a program met its goals and helped the people it was meant to help.
outcome expectanciesnoun: People's beliefs about what will follow an action can encourage them to do it or hold them back.
outcome interdependencenoun: Each person's actions affect what happens to others, so their results depend on one another.
outcome measuresphrase: Tools that track whether help is working by comparing a person's status across the course of care.
outcome researchphrase: Research that tests whether a treatment helps people and which treatment works best compared with other options.
outcome variablenoun: Researchers measure this result to study what changes it or what other factors help predict it.
outer earnoun: This sound-collecting region includes the visible ear, ear canal, and outward-facing surface of the eardrum.
outer hair cellsnoun: These specialized cochlear cells change length to strengthen and sharpen the vibrations used for hearing.
outer nuclear layernoun: This retinal layer contains the cell bodies of light-detecting rods and cones, including their nuclei.
outer plexiform layernoun: In this retinal layer, rods and cones form signaling connections with bipolar cells and horizontal cells.
outer psychophysicsnoun: This approach studies how the measurable strength of an outside stimulus relates to the strength of someone's sensory experience.
outer-directedadjective: A person's values, goals, and behavior are guided mainly by the standards of groups they identify with.
outercoursenoun: Sexual activity takes place without intercourse and may include genital touching or oral sex, depending on how the word is used.
outgroupnoun: A group someone does not belong to or identify with, often seen as the other side.
outgroup extremity effectnoun: Judgments about people outside one's own group, their behavior, and their creations tend toward exaggerated praise or criticism.
outgroup homogeneity biasnoun: People tend to see members of other groups as more alike than members of their own group.
outingnoun: Making a person's gay identity known to others, either about yourself or someone else.
outliernoun: A data point far from the others that can strongly change study results.
outpatientnoun: A patient who gets health or mental health care without staying overnight in a hospital.
outpatient commitmentnoun: A court requires someone to receive mental health treatment and monitoring while living in the community.
outpatient servicesphrase: Mental health care given without staying overnight in a hospital, clinic, office, or center.
outplacement counselingnoun: Workers whose jobs have ended receive help with finding new work and managing the emotional adjustment.
outputnoun: The information a computer gives back after it processes what was put into it.
output interferencenoun: Recalling some learned information makes other information from the same set harder to bring to mind.
outreachnoun: Bringing mental health, educational, or practical help directly to people who might not otherwise get services.
ovanoun: These reproductive egg cells carry genetic material and can combine with sperm during fertilization.
oval windownoun: This membrane-covered opening receives movement from the stapes bone and passes vibrations into fluid within the cochlea.
ovarian folliclenoun: A small structure inside an ovary surrounds and supports a developing egg cell before its release.
ovariectomynoun: A surgical procedure removes one ovary or both ovaries, often to treat disease or reduce disease risk.
ovarynoun: This reproductive organ supports egg development and produces hormones, including estrogen and progesterone, that influence many body processes.
over-the-counter (OTC)adjective: Medicines described this way can be bought without first obtaining a prescription from a medical professional.
overachievernoun: A person performs better than their scores on ability or intelligence tests would predict.
overactivitynoun: More movement and restlessness than usual, but not as intense as hyperactivity.
overageadjective: Someone described this way is older than the age usually associated with a particular grade, activity, or characteristic.
overattribution biasnoun: People may explain someone's behavior too strongly through personality while overlooking pressures from the situation.
overbreathingnoun: Breathing faster or deeper than the body needs, which can lower carbon dioxide too much.
overclassificationnoun: Children from ethnic minority groups may be assigned to special education disproportionately, raising concerns about how placement decisions are made.
overcompensationnoun: Someone responds to a real or perceived weakness by developing another strength or behavior beyond what is needed.
overconfidencenoun: Thinking you are better, more accurate, or more capable than you really are.
overcontrolledadjective: A person's behavior is excessively restrained, sometimes because of shyness or worries about being rejected.
overcorrectionnoun: A behavior therapy method where someone repeats a misbehavior the right way many extra times.
overcrowdingnoun: Having more people in a space than usual, often raising stress and sometimes behavior problems.
overdeterminationnoun: Psychoanalytic theory proposes that several unconscious influences can jointly produce a single symptom or behavior.
overdispersionnoun: Observed counts or category outcomes vary more widely than a statistical model expects, potentially making uncertainty estimates misleading.
overdose (OD)noun: Taking more of a drug than the body can handle, causing dangerous or even deadly effects.
Overeaters Anonymous (OA)noun: A voluntary peer organization uses twelve steps to support people seeking help with compulsive eating.
overexpectationnoun: Learned responses to separate cues weaken after those cues are combined but followed by only the previously learned outcome.
overextensionnoun: Young children may use one word too broadly, like calling every animal "doggie."
overgeneralizationnoun: Drawing broad conclusions from limited data or one case beyond what the evidence supports.
overheatingnoun: Too much heat in the environment that can stress the body and affect growth or health.
overidentificationnoun: Happens when a statistical model has extra information, so some unknown values can be figured out multiple ways.
overinclusionnoun: A person fails to rule out responses that are unsuitable or ineffective for a particular cue.
overintensitynoun: Arousal, effort, commitment, assertiveness, or concentration exceeds the level that best supports a person's performance.
overjustification effectphrase: Giving rewards for something someone already enjoys can reduce their inner interest and future effort.
overlapping psychological tasksnoun: Two tasks occur partly at the same time, often delaying the second response when their starting cues arrive close together.
overlapping waves theorynoun: A developmental theory proposes that children use several thinking strategies together, with each becoming more or less common over time.
overlearningnoun: Continuing practice after a skill is mastered helps it last longer and be remembered better.
overloadnoun: Feeling swamped when too much information and stimulation exceed a person's ability to notice, think, and cope.
overload principlenoun: Muscles are expected to grow or improve when training places demands near the limits of their current capacity.
overmatchingnoun: Researchers match participants on too many or unnecessary characteristics, potentially weakening a study's ability to reveal meaningful relationships.
overmedicationnoun: A person takes a medication, or several medications, in amounts greater than the prescribed doses.
overpayment inequityphrase: Feeling you are paid more than is fair compared with coworkers, which can create guilt or tension.
overpopulationnoun: An area contains more people or animals than is considered desirable, potentially contributing to crowding and stress.
overproductionnoun: When a species has more young than food, space, and other needed resources can support.
overprotectionnoun: Shielding a child so much that they do not learn independence and later struggle to adjust.
overreactionnoun: An emotional response that is much stronger than the situation calls for.
overregularizationnoun: A temporary language mistake where a child applies a rule too widely, like saying "breaked."
oversamplingnoun: Researchers deliberately include a larger share of certain groups than their population proportions to estimate those groups' characteristics more accurately.
overshadowingnoun: When two cues appear together, the stronger one grabs learning and weakens response to the other.
overshootnoun: During a nerve impulse, the voltage inside a cell briefly becomes positive compared with the outside.
overshootingnoun: A rapid eye movement carries the eyes past the location they were meant to look at.
overstaffingnoun: Managers judge that an organization or team employs more people than its work requires.
overtadjective: Clearly visible or openly expressed rather than hidden or secret.
overt behaviornoun: Actions are visible or otherwise directly noticeable to others without special equipment or training.
overt homosexualitynoun: An older expression describes attraction toward people of one's own gender that someone consciously acknowledges and outwardly expresses.
overt integrity testphrase: A job screening test that directly asks about honesty, theft, and attitudes toward breaking rules.
overt responsenoun: A reaction can be directly observed by others, such as a spoken answer or a pointing gesture.
overtonenoun: A sound component vibrates at a frequency above the fundamental, helping shape the sound's overall character.
overtraining syndromenoun: Excessive exercise without sufficient recovery produces lasting fatigue, declining performance, and changes in mood or motivation.
overvalued ideanoun: An inaccurate or exaggerated belief gains excessive personal importance but remains less fixed than a delusion.
overweightadjective: Carrying extra body fat beyond a healthy range for someone's age and body build.
oviductnoun: A reproductive tube carries egg cells away from an ovary toward other reproductive structures.
oviparitynoun: Animals reproduce by laying eggs, with the developing young completing their growth and hatching outside the parent's body.
OVLTabbreviation: A small brain structure detects substances circulating in blood because its protective barrier allows more direct exposure than most brain regions.
ovulationnoun: An ovarian follicle opens and releases an egg cell, technically a secondary oocyte in humans.
ovulatory cyclenoun: The ovary undergoes a repeating sequence of follicle growth, egg release, and changes in the tissue left behind.
ovumnoun: A mature egg is a reproductive cell carrying one chromosome set that can combine with sperm during fertilization.
oxazepamnoun: A benzodiazepine medicine slows nervous system activity and is used to treat anxiety and manage alcohol withdrawal.
oxidationnoun: A chemical substance loses electrons during a reaction, a process involved in the body's handling of many drugs.
oxidative stressnoun: Reactive chemicals overwhelm a cell's protective systems, potentially damaging its molecules and interfering with normal functioning.
oximetrynoun: A measurement estimates how much of the blood's oxygen-carrying hemoglobin has oxygen attached, often using light through skin.
oxycephalynoun: A skull has an unusually tall, pointed shape rather than a more rounded upper outline.
oxycodonenoun: An opioid medicine relieves pain by activating opioid receptors and can also cause sleepiness, slowed breathing, and dependence.
oxygen therapynoun: Medical treatment supplies extra oxygen to improve oxygen availability when a person's body is not getting enough.
oxytocicnoun: A medicine stimulates uterine contractions and may be used for childbirth, abortion care, or reducing bleeding after delivery.
oxytocinnoun: A brain-made chemical that helps with childbirth, milk release, and social bonding, especially closeness, trust, and caregiving.

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