Prefix

A prefix is a small unit of meaning which is added at the beginning of a word to make a new word with a different meaning.  Understanding what the prefix means can often help us work out what the new word means.  For example, the prefix un- has the meaning ‘not’, so we can work out that it will change the meaning of any word to a negative: kind/unkind, happy/unhappy.

Some prefixes have a similar meaning and are used with words spelt in particular ways.  For example the following prefixes also have a meaning of not:

il- used with words beginning with ‘l’ – illegal, illogical,

im- used with words beginning with ‘p’ – impatient, impossible, impractical

ir- used with words beginning with ‘r’ – irretrievable, irrational, irregular

dis- used with a variety of words and is not particularly related to the way the word is spelt – disappoint, discover, distaste

Other common prefixes include:

mis-	auto-
in-	bi
re-	aero-
de-	micro-
inter-	trans-
super-	tele-
anti-	com-
pre-	post-

See how many new words you and your child can make with these prefixes.  Discuss how the meaning of the original word has changed by adding the prefix.  Can you make a rule for what the prefix means and test it by adding it to other words?  Encourage your child to use a dictionary to help unpick the meanings.

For example:

Take the root word ‘press’.  Can you add any of the prefixes?

• depress
• repress
• compress

What do these words mean and how do they differ from the original word ‘press’?

You can extend this activity by seeing if you can add any suffixes to the word as well.  For example, impressed, compressing, suppression.