Humanities › English 35 Common Prefixes in English Share Flipboard Email Print Illustration by Melissa Ling. ThoughtCo English English Grammar An Introduction to Punctuation Writing by Richard Nordquist Richard Nordquist is a freelance writer and former professor of English and Rhetoric who wrote college-level Grammar and Composition textbooks. Updated May 04, 2019 If you were a prefix, you could change the same word in different ways.You could make a cycle a unicycle, a bicycle, or a tricycle.(Marcie Aboff and Sara Gray, "If You Were a Prefix." Picture Window Books, 2008) A prefix is a letter or a group of letters attached to the beginning of a word (or word root) that partly indicates its meaning. For example, the word prefix itself begins with the prefix pre-, which generally means "before" or "in front of." (By contrast, a letter or group of letters attaching to the end of a word is called a suffix.) Many of today's English words contain prefixes from Greek or Latin. Understanding the meanings of the most common prefixes can help us deduce the definition of new words that we run across in our reading, especially knowing that they can make a word mean its opposite, such as the difference between possible and impossible.Still, we do need to be careful. The same prefix may be spelled in more than one way (pre- and pro-, for instance), and some prefixes (such as in-) have more than one meaning (in this case, "not" or "without" versus "in" or "into"). Even so, being able to recognize prefixes can help us build our vocabularies. To Hyphenate or Not? Rules vary as to when a word should have a hyphen separating it from its prefix. Go by the dictionary if you are unsure. If you are writing a paper for a class and a particular style guide is used, such as MLA, the Chicago Manual of Style, or APA, the stylebook may have a hyphenation guide or a preferred dictionary to follow for which words to hyphenate and which to close up. If a prefix is attached to a proper noun, you generally hyphenate, such as pre-World War II or anti-American. The following table defines and illustrates 35 common prefixes. Common Prefixes Prefix Meaning Examples a-, an- without, lack of, not amoral, acellular, abyss, achromatic, anhydrous ante- before, earlier, in front of antecedent, antedate, antemeridian, anterior anti- against, opposite of anticlimax. antiaircraft, antiseptic, antibody auto- self, same autopilot, autobiography, automobile, autofocus circum- around, about circumvent, circumnavigate, circumscribe co- with, together co-pilot, co-worker, co-exist, co-author com-, con- together, with companion, commingle, contact, concentrate contra-, contro- against, opposite contradict, contrast, contrary, controversy de- down, off, away from devalue, deactivate, debug, degrade, deduce dis- not, apart, away disappear, disagreeable, disbar, dissect en- put into, cover with enclose, entangle, enslave, encase ex- out of, from, former extract, exhale, excavate, ex-president extra- beyond, outside, more than extracurricular, extramarital, extravagant hetero- different, other heterosexual, heterodox, heterogeneous homo-, homeo- same, alike homonym, homophone, homeostasis, homosexual hyper- over, more, beyond hyperactive, hypersensitive, hypercritical il-, im-, in-, ir- not, without illegal, immoral, inconsiderate, irresponsible in- in, into insert, inspection, infiltrate inter- between, among intersect, interstellar, intervene, interpenetrate intra-, intro- within, inside intravenous, intragalactic, introvert macro- large, prominent macroeconomics, macrostructure, macrocosm micro- very small microscope, microcosm, microbe mono- one, single, alone monocle, monologue, monogamy, monotony non- not, without nonentity, nonaggressive, nonessential, nonfiction omni- all, every omniscient, omnivorous, omniscient, omnidirectional post- after, behind postmortem, posterior, postscript, postoperative pre-, pro- before, forward precede, predict, project, prologue sub- under, lower submarine, subsidiary, substandard sym-, syn- same time, together symmetry, symposium, synchronize, synapse tele- from or over a distance telecommunications, telemedicine, television, telephone trans- across, beyond, through transmit, transaction, translation, transfer tri- three, every third tricycle, trimester, triangle, triathlon un- not, lacking, opposite of unfinished, unskilled, ungraceful, unfriendly uni- one, single unicorn, unicellular, unicycle, unilateral up- to the top or north, higher/better upbeat, updo, upgrade, upload, uphill, upstage, upscale, up-tempo Continue Reading Learn What an Affix Is in English Grammar and Morphology Which Words in a Title Should Be Capitalized? 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