The Collaborative International Dictionary
Psycho-
Psycho- \Psy"cho-\ A combining form from Gr. psychh` the soul, the mind, the understanding; as, psychology.
Douglas Harper's Etymology Dictionary
psycho-
word-forming element meaning "mind, mental; spirit, unconscious," from Greek psykho-, combining form of psykhe (see psyche). It also was used to form compounds in Greek, such as psychopates "soul-beguiling."
Wiktionary
psycho-
pre. Forms terms relating to the soul, the mind, or to psychology.