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").
"the sum of scientific knowledge concerning drugs," 1721, formed in Modern Latin (1680s) from pharmaco- (see pharmacy) + -logy. It includes pharmacy (the art of preparing drugs) and also pharmacodynamics (what is known concerning their action). Related: Pharmacological.