psychotherapy n.

word-forming element meaning "mind, mental; spirit, unconscious," from Greek combining form of psykhē "the soul, mind, spirit; life, one's life, the invisible animating principle or entity which occupies and directs the physical body; understanding, the mind (as the seat of thought), faculty of reason" (see psyche). It also was used to form compounds in Greek, such as psychapates "soul-beguiling" (with apate "deceit").

1846, "medical treatment of disease," from Modern Latin therapia, from Greek therapeia "curing, healing, service done to the sick; a waiting on, service," from therapeuein "to cure, treat medically," literally "attend, do service, take care of" (see therapeutic).

"specialist in or practitioner of psychotherapy," 1894, from psychotherapy + -ist.