An affix is a morpheme that is attached to a base morpheme to form a word. An affix can be a prefix (attached before another morpheme), a suffix (attached after another morpheme), an infix (inserted within another morpheme), a circumfix (attached before and after another morpheme), or a suprafix (attached suprasegmentally to another morpheme). Affixes are bound morphemes by definition. Prefixes and suffixes may be separable affixes.

Affixes are central to the process of agglutination.

¹ English infixes only exist in exclamatory constructions like the given example.
² English circumfixes do not exist other than en- -en, which is not productive now.

See also

• derivation
• list of English prefixes
• list of English suffixes