suffix

Everyday

1. A suffix is a group of letters added to the end of a word to make a new word or change how it is used, like -ful in «hopeful», -ness in «kindness» or -ed in «jumped». tree →
2. In maths and computing, a suffix can be letters or a number added to the end of a name or code. tree →

In the lessons

In English grammar and spelling lessons (and SATs), suffixes are key: -s and -es make plurals, -ed and -ing change verb tense, -er and -est compare, and -ful, -less, -ness, -ment, -ly, -tion make new words. Spelling rules apply: double the consonant (run → running), drop the e (hope → hoping), change y to i (happy → happiness). Phrases: add a suffix, the suffix -ly, root word and suffix.

Examples

• Add the suffix -ful to «help» to make «helpful». tree →
• «-ly» is a suffix that turns «quick» into «quickly». tree →
• The suffix -less means «without», as in «homeless». tree →
• Underline the suffix in «enjoyment». tree →
• Adding -ing to «swim» doubles the m. tree →
• The suffix -er can mean «a person who does it», as in «teacher». tree →
• When you add the suffix -ness to «happy», y changes to i. tree →
• Some words have two suffixes, like «care-ful-ly». tree →

Note

Countable: a suffix, suffixes (add -es after x). Pronounced «SUF-ix». A suffix goes at the END; a prefix goes at the START (un- in «unhappy»). The word you add it to is the root or base word. A suffix can change the word class: «kind» (adjective) → «kindness» (noun).