AFFIX. An element added to a WORD, BASE, or ROOT to produce an inflected or derived form, such as -s added to house to form houses and re-added to write to form re-write. Affixed elements include the PREFIX (anti- in anti-war), the SUFFIX (-ity in formality), the INFIX (-m- in recumbent but not cubicle, a relic from Latin), and the INTERFIX (reduced and in sun ‘n’ sand). See DERIVATION, ENDING, WORD-FORMATION.

af·fix • v. / əˈfiks/ [tr.] stick, attach, or fasten (something) to something else: he licked the stamp and affixed it to the envelope.• n. / ˈaˌfiks/ Gram. an additional element placed at the beginning or end of a root, stem, or word, or in the body of a word, to modify its meaning. See also infix, prefix, suffix.DERIVATIVES: af·fix·a·tion / ˌafikˈsāshən/ n.

affix vb. XV. — OF. affixer or medL. affixāre, f. AF- + fixāre FIX.
So affix sb. (cf. PREFIX, SUFFIX). XVII.