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.
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.”
They can also make a word negative or express relations of time, place or manner. Here are some examples:
| Base word | Type of meaning | Prefixed word |
| possible | opposite | impossible |
| able | opposite/negation | unable |
| payment | negation | non-payment |
| war | time (before) | pre-war |
| terrestrial | place (outside of/beyond) | extraterrestrial |
| cook | manner (too much) | overcook |
Example:
- That he was unable to do, even if it were true, which he doubted.
- It is virtually impossible that he had all the same information as the actual president.
- The meat was overcooked and quite tasteless.
The most 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/opposed to | anti-government, anti-racist, anti-war |
| auto- | self | autobiography, automobile |
| 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- | reverse or change | de-classify, decontaminate, demotivate |
| dis- | reverse or remove | disagree, displeasure, disqualify |
| down- | reduce or lower | downgrade, downhearted |
| en- | put into, cover with | enclose, entangle, enslave, encase |
| ex- | out of, from, former | extract, exhale, excavate, ex-president |
| extra- | beyond, outside, more than | extraordinary, extraterrestrial |
| hetero- | different, other | heterosexual, heterodox, heterogeneous |
| homo-, homeo- | same, alike | homonym, homophone, homeostasis |
| hyper- | extreme, over, more, beyond | hyperactive, hypertension |
| il-, im-, in-, ir- | not, without | illegal, impossible, insecure, irregular |
| inter- | between, among | interactive, international |
| 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 |
| mega- | very big, important | megabyte, mega-deal, megaton |
| mid- | middle | midday, midnight, mid-October |
| mis- | incorrectly, badly | misaligned, mislead, misspelt |
| non- | not | non-payment, non-smoking |
| omni- | all, every | omniscient, omnivorous, omniscient, omnidirectional |
| over- | too much | overcook, overcharge, overrate |
| out- | go beyond | outdo, out-perform, outrun |
| post- | after | post-election, post-war |
| pre- | before | prehistoric, pre-war |
| pro- | in favour of | pro-communist, pro-democracy |
| re- | again | reconsider, redo, rewrite |
| semi- | half | semicircle, semi-retired |
| sub- | under, below | submarine, sub-Saharan |
| sym-, syn- | same time, together | symmetry, symposium, synchronize, synapse |
| super- | above, beyond | super-hero, supermodel |
| tele- | at a distance | television, telepathic |
| trans- | across | transatlantic, transfer |
| tri- | three, every third | tricycle, trimester, triangle, triathlon |
| ultra- | extremely | ultra-compact, ultrasound |
| un- | remove, reverse, not | undo, unpack, unhappy |
| under- | less than, beneath | undercook, underestimate |
| uni- | one, single | unicorn, unicellular, unicycle, unilateral |
| up- | to the top or north, higher/better | upbeat, updo, upgrade, upload, uphill, upstage, upscale, up-tempo |
