English prefixes,
actually explained

From Greek "a-/an-" (without, not): negates the root that follows, as in amoral (without morals) or atypical (not typical).

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.

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.

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 going beyond or being above, as in surpass and surface.

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.

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.

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): appears in words about humankind, like anthropology and philanthropist.

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" (beside, near): signals something secondary or additional, as in byproduct and bystander.

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): appears in words about the universe and the world, like cosmology and cosmopolitan.

Means "cold" or "freezing": cryogenic, cryotherapy, cryonics, cryopreservation.

From Greek "kryptos" (hidden, secret): appears in words about codes and secrets, like cryptography and decrypt.

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 society and population, like democracy and demography.

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): appears in words about peoples and cultures, like ethnic and ethnography.

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): appears in words about shape and transformation, like morphology and metamorphosis.

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 and emotional words, like pathology and 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): appears in words about heat and temperature, like thermometer and thermostat.

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.