A prefix is one or more letters added before a base word to change its meaning. Prefixes have different functions. They may make the word negative (-un, in), by showing repetition (-re), or by showing support (-pro).
Prefixes are mostly used to shorten phrases. For example, if you want to say that someone is “eating too much“, you can simply say that they are “overeating“.
Here is a list of prefixes from a-z and their meaning and examples.
Prefix | Meaning | Example |
ab | away, from | abstract, abort, abrupt |
a | not or without, a state of being | atypical, amoral, anew |
ad | to, toward, near | adjust, adapt, adverb |
ambi | both | ambivalent, ambilateral |
ante- | before | anteroom, antechoir |
anti- | against, opposing | antibiotic, antibacterial |
arch | chief, most important | archenemy, archbishop |
a | at, in, on, to | awake |
at | to, toward | attend |
auto | self | automatic, autobiography |
be | cause to be | bespoke, belittle |
bene | good | benefactor, benediction |
bi | two, twice | bicycle, billingual |
circum- | around | circumference, circuit |
co | with, together | collude, coalition |
con | jointly | connect, consensus |
contra | against | contraindicate, contraceptive |
counter | opposite | counteract, counterbalance |
co- | with | co-author, co-parent |
deca | ten | decagon, decagram |
demi | half | demibillionaire, demivoice |
de- | off, down, away from | descend, deactivate, declog |
dia | through, across | diagonal, diagram |
dis- | opposite of, not | disadvantage, discredit |
di | two | dilemma |
dys | bad, abnormal | dyslexia |
em- | cause to | embitter, empower |
em-, en- | cause to, put into | enlighten, embody |
en- | to cause, provide | ensure |
endo | internal | endoscopy |
epi- | upon, close to, after | epidemic, epilogue |
equi | equal | equilibrium |
ethno | race, nation | ethnocentric |
ex- | former, out of | ex-wife, exclude |
extra- | outside, beyond | extramarital, extracurricular |
fore- | before | forefather, foresee |
homo- | same | homonym, homosexual |
hyper- | beyond, more than, more than normal | hypersensitive, hyperbole |
im-,-in | in | improper, influence |
il-, im-, in-, ir- | not | illogical, impossible, inappropriate, irrational |
infra- | beneath, below | infrastructure, infrahuman |
im-, in- | into | inject, imbibe |
inter-, intra- | between | interact, intravenous |
macro- | large | macrolanguage, macrohistory |
micro- | small | microchip, microorganism |
mid- | middle | midterm, midpoint |
mis- | wrongly | misuse, mismanage |
mono- | one, singular | monologue, monopoly |
non- | not, without | nonfiction, nonpayment |
omni- | all, every | omnipresent, omniscience |
over- | over | overrule, overkill |
para- | beside, closely related | paragraph, paradigm |
post- | after | postgame, postseason |
pre- | before | prenatal, prenuptial |
re- | again | restart, relive |
semi- | half | semicircle, semiformal |
sub- | under | submarine, subordinate, subtitle |
therm- | heat | thermal, thermonuclear |
trans- | across, beyond | translucent, transparent |
tri- | three | tristate, triathlon, tricolor |
under- | under | underpay, undergo |
un- | not | unable, uncommon, unhappy |
uni- | one | unicameral, unison |
Tips:
When to use hyphens with prefixes:
a. Prefix with a proper noun except for the word “transatlantic“, the only word that does not follow this rule on proper nouns.
pro-China protesters |
trans-American flights |
b. If the word with the prefix already exists, use a hyphen.
resign = voluntarily leave a job or other position |
re-sign = sign (a document) again |
c. all-, ex– (former), and self–
all-knowing |
ex-husband |
self-care |
Only use a hyphen when the meaning of ex- is “former” or “in the past.”
Note:
The prefix “extra” does not need a hyphen if it means “outside of“.
extraordinary |
extravagant |