To fix; fasten, join, or attach; conjoin, add, or append; make an adjunct or part of: followed by to.Synonyms Add, Affix, Annex, etc. (see add), suffix, superadd, tack on, fasten on, join.n. That which is joined, attached, or added; an addition or attachment.n. In philology, a syllable or letter, prefix or suffix, attached to a word or a verbal root or stem, as in good-ness, veri-fy, civil-ize, un-able, un-con-form-able.n. In decorative art, any small feature, as a figure, a flower, or the like, added for ornament to a vessel or other utensil, to an architectural feature, etc.: used especially with reference to ceramics and bronzes.n. In mathematics, the complex number x + iy is denoted by a single letter, z; the point P, (x, y), is then called the affix of the value z; the number z is also spoken of as the affix of the point P.