A prefix is a group of letters added to the beginning of a word to change its meaning. Un- and dis- usually mean not: unhappy, dislike.
Mis- means wrongly: misspell, misbehave. Re- means again: rebuild, rewrite. Pre- means before: preview, preheat.
When you add a prefix, do not change the spelling of the root word. That is why disappear has one s, but dissatisfied has two.
Knowing prefixes helps you work out the meaning of long words you have never seen before, such as preheat or rediscover.
Worked example
What does “misunderstand” mean?
- The prefix mis- means wrongly.
- The root word is understand.
Answer:to understand something wrongly
Key words
- prefix
- letters added to the start of a word
- root word
- the main word before a prefix or suffix
- meaning
- what a word tells us
Practise this
New questions every time.
Common Core-referenced: L.3.4a, L.3.4b