1610s, "skilled in a particular art or subject," formed in English from technic + -al (1), or in part from Greek tekhnikos "of art; systematic," in reference to persons "skillful, artistic," from tekhne "art, skill, craft" (see techno-).
The sense narrowed to "having to do with the mechanical arts" (1727). Basketball technical foul (one which does not involve contact between opponents) is recorded from 1934. Boxing technical knock-out (one in which the loser is not knocked out) is recorded from 1921; abbreviation TKO is from 1940s. Technical difficulty is from 1805.