English
What is a prefix?
Quick answer
A prefix is a group of letters added to the start of a word to change its meaning, like un- in unhappy, re- in replay or dis- in disappear.
In one sentence
A prefix is a small word part fixed to the front of a word to make a new word with a different meaning.
Explained
Take the word happy. Add un- to the front and you get unhappy, which means "not happy". Un- is a prefix. The word it attaches to (happy) is called the root word.
Prefixes are powerful because one prefix can explain dozens of words. Once you know that re- means "again", you can work out redo, rebuild, reread, refill and replay without a dictionary.
Common prefixes:
| Prefix | Meaning | Examples |
|---|---|---|
| un- | not / reverse | unkind, untie, unpack |
| dis- | not / opposite | disagree, dislike, disappear |
| mis- | wrongly | misspell, misbehave, mislead |
| re- | again / back | replay, return, rebuild |
| pre- | before | preview, prehistoric |
| in-, im-, il-, ir- | not | incorrect, impossible, illegal, irregular |
| sub- | under | submarine, subway |
| super- | above / beyond | superhero, supermarket |
| inter- | between | international, interact |
| anti- | against | antiseptic, anticlockwise |
| auto- | self | autograph, autobiography |
Spelling tip: adding a prefix almost never changes the spelling of the root word. Just join them: dis + satisfied = dissatisfied, mis + spell = misspell, un + necessary = unnecessary. Double letters appear only when the prefix ends with the same letter the root starts with.
Many prefixes make antonyms: possible / impossible, tidy / untidy, honest / dishonest. A prefix can also add a syllable at the front, so split long words at the prefix to read them: un-be-liev-a-ble.
submarine
bike
planet
Examples
- The magician made the rabbit disappear.
- Please rewrite this neatly.
- It is impolite to interrupt.
- She misread the sign and took the wrong bus.
- My uncle unpacked the shopping.
Common mistakes
- Dropping or adding letters: dissapear (should be disappear), mispell (should be misspell).
- Picking the wrong "not" prefix: unpossible should be impossible. Learn the common pairs.
- Thinking every word starting with these letters has a prefix. Uncle and real are not un- + cle or re- + al.
Quick quiz
Prefixes
Check what you know with 5 quick questions.
Question 1 of 5
What does the prefix un- usually mean?
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Spelling practice with prefixes
For grown-ups
Related topics
Suffixes
A suffix is a group of letters added to the end of a word to change its meaning or job, like -ful in helpful, -ness in kindness or -ed in jumped.
Antonyms
An antonym is a word that means the opposite of another word, like hot and cold, up and down, or happy and unhappy.
Syllables
A syllable is a beat in a word, built around one vowel sound. Cat has one syllable, rab-bit has two, el-e-phant has three.
Synonyms
A synonym is a word that means the same or nearly the same as another word, like big and large, or happy and cheerful.
Homophones
Homophones are words that sound the same but have different meanings and usually different spellings, like there, their and they're, or see and sea.
Plurals
A plural means more than one. Most nouns add -s (cats) or -es (boxes), but some change in other ways, like babies, leaves, mice and children.