A prefix is a letter or a set of letters attached to the start of a word (or word root) that partly indicates its meaning. For instance, the word prefix itself begins with the prefix pre-, which usually means “before” or “in front of.” Below is a list of 35 common prefixes in English.
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 |
| 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 |
