Prefixes un-, re-, and dis-

Read and understand three of the most common prefixes in English.

A prefix is a word part added to the front of a base word to change its meaning. Three of the most common are 'un', 're', and 'dis'. 'Un' usually means not or the opposite of: unhappy means not happy, and unlock means the opposite of lock. 'Re' means again or back: reread means read again, and repay means pay back.

'Dis' means not or the opposite of: dislike means not like, and disappear is the opposite of appear. When you meet a word like 'rebuild', cover the prefix, read the base 'build', then add the prefix's meaning: build again. This gives you both how to say the word and what it means.

• 1A prefix goes at the front and changes meaning.
• 2un- and dis- = not or opposite; re- = again or back.
• 3Cover the prefix, read the base, then add the meaning.