The word affix is a linguistic term. Affixes are members of a sub-group of the class of morphemes, and the sub-group is again further divided. An affix is 'a recognised fragment of a language that is used regularly to build new words, or convert other words'. Such parts of words as '-ing', 'un-', 'anti-'and '-less' are all affixes.
- An affix that goes at the front of other units (that precedes them) is called a prefix., 'post-', 'inter-' and 'pre-' are all examples of prefixes.
- An affix that goes at the end of a word is called a suffix. '-ator', '-able', '-ed' and '-ition' are all suffixes.
- Other languages have infixes as well.
Note that there are in essence two kinds of affix in English to judge by their position in words. There are also two main ways in which they are used. Inflectional affixes are those which are used for grammatical purposes. '-ed', for example, changes the tense of a verb from the present to the past, without in itself having much meaning; '-ation' changes a verb to an abstract noun.
Other affixes, those which have meaning, are lexical affixes. These clearly alter the meaning of the word to which they are added. 'pre-', for example, means 'before', and '-ist', when used with the name of a system of belief, means 'a person who holds the belief': a 'Marxist' is someone who follows the ideas of Karl Marx. (It can also be used epithetically to make the adjective that describes such a system, or a believer in it.)