A single beginning can change everything: happy becomes unhappy, possible becomes impossible. Learn prefixes and unlock thousands of words without memorising them one by one. 127 prefixes explained step by step.
They reverse or deny the meaning of the base word (unhappy, disagree, non-stop).
From Greek "a-/an-" (without, not): expresses the complete absence of a quality — the opposite of whatever root follows.
Signals active opposition or protection: antibiotic, antivirus, antisocial, antidote.
Negates or reverses meaning: disagree, disconnect, disappear, dishonest.
Formal Latin-origin negation with four phonetic forms: invisible, impossible, illegal, irregular.
Negates neutrally and objectively without implying fault: nonstop, nonprofit, nonfiction.
The most common negative prefix in English: turns happy into unhappy and lock into unlock.
They indicate undoing or going back (redo, decode, disconnect).
Signals opposition or contrary action: contradict, contraband, contrast, contraception.
Signals an opposing or responsive action: counterattack, counterpart, counterfeit, counterproductive.
Reverses or removes an action or condition: defrost, decode, deactivate, debug, dehydrate.
Signals doing something again or returning to a previous state: redo, return, reopen.
They place something in space or time (preview, subtitle, interact, overtime).
Signals before or in front of: antecedent, anteroom, antenatal, antebellum, antediluvian.
Signals around or surrounding something: circumference, circumstance, circumnavigate, circumspect.
Signals downward movement or reduction: download, downgrade, downstairs, downside.
Means "inside" or "internal": endoscopy, endocrine, endemic, endorphin, endoskeleton.
Signals upon, over, or after: epidemic, epilogue, epicenter, epidermis, episode.
Means "outside" or "external": exotic, exoskeleton, exoplanet, exodus, exosphere.
Signals outside of, beyond, or in an additional degree: extraordinary, extraterrestrial, extracurricular.
Signals a front position or anticipation of something: forecast, forearm, forehead, foresee.
Means "below" or "beneath a threshold": infrastructure, infrared, infrasound, infrasonic.
Signals a relationship or action between two or more things: international, interact, internet.
Signals within or inside a single entity: intravenous, intranet, intramural, intracellular.
Signals the central point or middle of something: midnight, midday, midterm, mid-air.
Signals beside, beyond, or an auxiliary role: paramedic, paranormal, paragraph, parallel.
Means "around" or "near": perimeter, peripheral, periscope, period, peril, perennial.
Signals time or position after something else: postgraduate, postpone, postwar, postmortem.
Signals something that exists or happens before something else: preview, prepare, prehistoric.
Signals the first of its kind, the original, or a primitive version: prototype, protocol, protagonist.
Signals backward movement or reference to the past: retroactive, retrospective, retrofit, retrograde.
Signals position below or a lower level: subway, submarine, subtitle, subconscious.
From French/Latin "sur-" (over, above): signals surpassing a limit, covering a surface, or going beyond the expected.
Signals action or communication at a distance: television, telephone, telescope, telework.
Signals crossing, transformation, or movement through: transport, transform, translate, transfer.
Signals upward movement or improvement: upgrade, update, upload, upcoming, upstairs.
Signals the person who holds second rank or can act in place of the first: vice-president, viceroy.
They express amounts, proportions, or scale (monologue, bicycle, microscope, megaphone).
Means "both" or "on both sides": ambidextrous, ambiguous, ambivalent, ambiguity, ambivert.
Signals the highest rank or supreme example of a type: archbishop, archenemy, archetype.
Signals two or double: bicycle, bilingual, bilateral, bifocal, biannual.
Signals excess or a level above normal: hyperactive, hypertension, hyperbole, hyperlink.
Signals a level below normal: hypothermia, hypoglycemia, hypotension, hypothesis.
Means "equal" or "same": isotope, isosceles, isometric, isobar, isotherm, isomer.
Means "thousand" in the metric system: kilometer, kilogram, kilowatt, kilobyte.
Signals large scale or breadth: macroeconomics, macroscopic, macronutrient.
Signals one million units or enormous size: megabyte, megawatt, megapixel, megacity.
Signals extreme smallness or one millionth of a base unit: microscope, microphone, microchip.
Signals a small or reduced version: miniature, minimum, minibar, miniseries, minimal.
Signals one or uniqueness: monologue, monopoly, monotone, monochrome, monolingual.
Signals many or multiple: multiply, multicultural, multimedia, multitask, multilingual.
Signals one billionth (10⁻⁹) or an extremely small scale: nanotechnology, nanometer, nanobot.
Signals all or everywhere: omnipotent, omniscient, omnivore, omnipresent.
Signals surpassing someone or something, or moving outward: outsell, outperform, outcome.
Signals excess or going beyond the normal limit: overwork, overlook, overcome, overtime.
Signals all or universal inclusion: pandemic, panorama, panacea, Pan-American.
Signals many or multiple: polygon, polyglot, polymer, polymath, polyphony.
Means "four": quadrant, quadruple, quadrilateral, quadruped, quadruplets, quadriceps.
Signals half or partial degree: semicircle, semifinal, semiconductor, semicolon.
Signals a superior level or top quality: superhero, supernatural, supermarket, superhuman.
Signals three: triangle, trilogy, tricycle, triathlon, tripod, trimester.
Signals beyond normal limits or an extreme degree: ultraviolet, ultrasound, ultramarathon.
Signals insufficiency or less than the required level: underestimate, underpaid, undercooked.
Means "one" or "single": uniform, unique, universe, unity, unicorn, unify.
Prefixes with particular or specialized uses.
Means "away from" or "off": absent, abstract, abnormal, absorb, abuse, abandon, abrupt.
Means "toward" or "near": adapt, advance, admit, adopt, advantage, advertise, advise.
Means "air" or relating to flight: aerobic, aerosol, aerospace, aerodynamic, aeronautics.
From Greek "anthropos" (human being): the root of academic words about human study, human nature, and humanity's place in the world.
Means "water": aquarium, aquatic, aquifer, aqueduct, aquaculture, aqueous.
Signals relation to stars or outer space: astronaut, astronomy, astrophysics, asteroid.
Signals self-action or automaticity: automatic, autobiography, autopilot, autograph.
A native English prefix meaning "around," "make," or intensifying: become, believe, belong.
Signals something good or beneficial: benefit, beneficial, benevolent, benefactor, benign.
Signals relation to life or biological processes: biology, biography, biodiversity, biofuel.
From Old English "bi" (near, beside): marks something secondary, incidental, or happening at the edge of the main activity.
Means "heart": cardiogram, cardiology, cardiovascular, cardiac, cardiomyopathy.
Means "down," "against," or "completely": catastrophe, catalyst, catalog, cataclysm, catapult.
Means "time": chronology, chronic, synchronize, anachronism, chronicle.
Signals time or temporal relationship: chronological, chronology, chronicle, chronic, anachronism.
Signals joint action or union: cooperate, combine, connect, coexist, coworker.
Means "together" or "with": connect, combine, cooperate, communicate, compare.
From Greek "kosmos" (universe, order): found in words about space, the whole world, and universal scale.
Means "cold" or "freezing": cryogenic, cryotherapy, cryonics, cryopreservation.
From Greek "kryptos" (hidden): found in words about secret codes, concealed things, and digital security.
Means "hidden" or "secret": cryptography, cryptocurrency, cryptic, cryptogram, cryptologist.
Signals relation to computer systems or the internet: cybersecurity, cyberspace, cybercrime.
From Greek "demos" (people): appears in words about governance, population science, and public health.
Means "skin": dermatology, dermal, dermatitis, dermatologist, epidermis.
Means "through," "across," or "between": diameter, diagonal, dialogue, diagnosis, diagram.
Signals dysfunction, difficulty, or abnormality: dyslexia, dysfunction, dystopia, dysphoria.
Signals relation to the environment or ecology: ecosystem, ecology, eco-friendly, ecotourism.
Signals relation to electricity: electricity, electrode, electrocardiogram, electrolyte.
Means "make," "cause to be," or "put into": enable, empower, enrich, encourage.
From Greek "ethnos" (nation, people): found in academic words about cultural groups, anthropology, and social science.
Signals something good, normal, or favorable: euphoria, euthanasia, eulogy, euphemism.
Signals a former role or outward movement: ex-president, exit, export, exclude, expand.
Means "stomach" or relating to food and digestion: gastronomy, gastritis, gastropod.
Signals relation to the Earth or geography: geography, geology, geometry, geothermal.
Means "sun": heliocentric, helium, heliograph, heliotherapy, heliosphere, heliostat.
Means "blood": hemoglobin, hematology, hemorrhage, hemophilia, hematoma.
Means "different" or "other": heterogeneous, heterodox, heteronym, heterozygous.
Means "whole" or "complete": hologram, holistic, holography, holocaust, Holocene.
Means "same" or "equal": homogeneous, homonym, homophone, homologous, homozygous.
Signals relation to water or hydrogen: hydrogen, hydroelectric, hydrocarbon, hydrology.
Signals something bad, deficient, or wrong: malfunction, malnutrition, malpractice, malice.
Signals beyond, transformation, or self-reference: metaphor, metamorphosis, metadata, metaverse.
Signals doing something incorrectly or badly: misunderstand, mislead, misspell, mistake.
From Greek "morphē" (form, shape): found in biology, linguistics, and technology to describe structures and transformations.
Signals something new or a revival of something earlier: neologism, neoclassical, neonatal.
Signals relation to the nervous system: neuron, neuroscience, neurotransmitter, neuroplasticity.
Means "against," "in the way," or "toward": object, observe, obtain, obvious, obstacle, obscure.
Means "straight" or "correct": orthodontist, orthopedic, orthodox, orthography, orthogonal.
Means "bone": osteoporosis, osteology, osteopathic, osteoblast, osteoarthritis.
Means "ancient" or "primitive": paleontology, Paleolithic, Paleocene, paleoanthropology.
From Greek "pathos" (suffering, feeling): appears in medical terms about disease and in emotional words like empathy.
Signals through, completely, or with intensity: perfect, permanent, persist, pervade, persuade.
Means "love" or "strong affinity for": philosophy, philanthropy, philharmonic, philology.
Means "sound" or "voice": phonetics, phoneme, phonics, phonology, phonograph.
Signals relation to light or photography: photograph, photosynthesis, photon, photovoltaic.
Signals support for something or forward movement: progress, promote, provide, pro-democracy.
Signals something false or pretending to be what it is not: pseudonym, pseudoscience, pseudocode.
Signals relation to the mind or psychology: psychology, psychotherapy, psychoanalysis.
Means "fire": pyrotechnics, pyromaniac, pyrolysis, pyroclastic, pyrometer.
Means "society" or "social": sociology, socioeconomic, sociopath, sociocultural.
Signals union or simultaneity: synonym, synthesis, syndrome, synergy, symphony.
Means "earth" or "land": territory, terrain, terrestrial, terraform, terracotta.
Means "god": theology, theocracy, theism, theodicy, theocentric.
From Greek "thermē" (heat): one of science's most useful roots, appearing in physics, medicine, and everyday technology.
Signals relation to heat or temperature: thermometer, thermostat, thermodynamics, thermal.
A native English prefix meaning "back" or "against": withdraw, withstand, withhold, wither.
Means "foreign" or "strange": xenophobia, xenon, xenophile, xenograft, xenobiotic.