in grammar, "word or syllable or two syllables (rarely more) affixed to the beginning of a word to qualify its meaning or direct its application," 1640s, from Latin praefixum, noun use of neuter past participle of praefigere "fix in front, fasten on before," from prae "before" (see pre-) + root of figere "to fasten, fix" (from PIE root *dheigw- "to stick, fix"). Related: Prefixal.
early 15c., prefixen, "appoint beforehand," from Old French prefixer, from pre- "before" (see pre-) + *fixer (see fix (v.)). Also compare Latin praefixus, past participle of praefigere. Meaning "to place at the beginning" is from 1530s; of words or parts of words from c. 1600. Related: Prefixed; prefixing.