An affix is any group of letters added to a word. There are three kinds of affixes:
- a prefix is letters added to the front of a word (cf prefix forms, augment);
- an infix is something added to the middle of a word (cf hifil, tense formative);
- a suffix is something added to the end of a word (cf pronominal suffix, case endings).
Affixation is, thus, the linguistic process speakers use to form new words by adding sounds (affixes) at
- the beginning (prefix),
- the middle (infix) or
- the end (suffix) of words.