A prefix is a word or syllable added at the beginning of another word that changes its meaning. Some negate the original meaning, some change the word to mean the opposite, others expand on the meaning.
Here are some examples:
| Prefix |
Meaning |
Examples |
| a | not | amoral, asymmetric |
| anti | opposite, against | anti-inflammatory, antibiotic |
| auto | self | automobile, autobiography |
| bi | two | biweekly |
| co | together | cooperation, coexist |
| contra | against | contraindicate |
| de | reverse, undo | degrade, deactivate |
| dis | opposite of | disappear, disagree, disconnect |
| down | reduce | downgrade, downshift |
| dys | negative | dysfunction |
| ex | out, previous | ex-boss |
| extra | greater | extraordinary |
| fore | before | foresight |
| hemi | half | hemisphere |
| hetero | different | heterosexual |
| homo | same | homophobia |
| hyper | more | hyperactive, hypertension |
| hypo | less | hypoglycemia |
| il | not | illegal, illogical |
| im | lack of, not | imbalance, impossible |
| in | not, without | inactive, injustice, invisible |
| infra | below | infrared |
| inter | between | interactive |
| intra | within | intracellular |
| ir | without | irregular, irreversible |
| mal | bad | malodorous |
| mega | large, superlative | megastore, megaphone |
| micro | small | microscope |
| mid | middle | midterm, midseason |
| mis | incorrect, wrong | misunderstand, misplace |
| mono | same | monotone |
| non | not | nonfiction, nonsense |
| over | too much | overcook, overdone |
| pan | all | pan-African |
| para | beside, beyond | paranormal, paramilitary |
| post | after | postoperative |
| pre | before | preassembled, preschool |
| pro | for, before | proactive |
| re | again | reconsider, re-evaluate, rewrite |
| self | acting by itself | self-cleaning |
| semi | half | semi-retired |
| sub | below | subzero, sub-Saharan Africa, submarine |
| super | above, more | supermarket |
| trans | across, change | transatlantic |
| ultra | beyond | ultraviolet, ultramarathon |
| un | not, opposite | unhappy, unkind, unusual |
| xeno | foreign | xenophobia |
© Andrea Paulsen