"model, first form, original pattern from which copies are made," 1540s [Barnhart] or c. 1600 [OED], from Latin archetypum, from Greek arkhetypon "pattern, model, figure on a seal," neuter of adjective arkhetypos "first-moulded," from arkhē "beginning, origin, first place" (verbal noun of arkhein "to be the first;" see archon) + typos "model, type, blow, mark of a blow" (see type).
The Jungian psychology sense of "pervasive idea or image from the collective unconscious" is from 1919. Jung defined archetypal images as "forms or images of a collective nature which occur practically all over the earth as constituents of myths and at the same time as autochthonous individual products of unconscious origin." ["Psychology and Religion" 1937]