word-forming element, in English meaning usually "out of, from," but also "upwards, completely, deprive of, without," and "former;" from Latin ex "out of, from within; from which time, since; according to; in regard to," from PIE *eghs "out" (source also of Gaulish ex-, Old Irish ess-, Old Church Slavonic izu, Russian iz). In some cases also from Greek cognate ex, ek. PIE *eghs had comparative form *eks-tero and superlative *eks-t(e)r-emo-. Often reduced to e- before -b-, -d-, -g-, consonantal -i-, -l-, -m-, -n-, -v- (as in elude, emerge, evaporate, etc.).

1827, originally short for ex-Catholic; see ex-. Since 1929 as abbreviation for ex-wife, ex-husband, etc. Also used in some commercial compound words for "from, out of."

"one who serves or has served in the armed forces," 1899, from service (n.) + man (n.).

Latin legal term, "on the one side only," from ex "out of" (see ex-) + parte, ablative of pars "a part, piece, a division, a fraction, a side of the body" (from PIE root *pere- (2) "to grant, allot").

Latin, literally "from the (teacher's) chair," from ex "out of" (see ex-) + cathedra (see cathedral).

Latin, "in discharge of one's duties," literally "out of duty," from ex "out of" (see ex-) + officio, ablative of officium "duty" (see office).

Latin, literally "out of the books (of)," from ex "out of" (see ex-) + ablative plural of liber "book" (see library). Hence, ex-librist (1880).

Latin, literally "out of nothing," from ex "out of" (see ex-) + nihilo, ablative of nihil "nothing" (see nil).

from Medieval Latin ex postfacto, "from what is done afterwards." From facto, ablative of factum "deed, act" (see fact). Also see ex-, post-.

1650s, "physician; medical student," from Latin medicus "physician" (see medical (adj.)); modern sense of "serviceman in a military medical corps" is recorded by 1925.