Online Etymology Dictionary

psilosis (n.): "loss of hair through disease," 1837, medical Latin, from Greek psilosis "a stripping of hair," from psiloun "to strip of hair," from psilos "bare" (see psilo-).
psionic (adj.): 1952, from psi + ending from electronic, etc.
psittacine (adj.): "pertaining to parrots," 1826, from Latin psittacinus, from psittacus "parrot," from Greek psittakos "a parrot," said to be a foreign word.
psittacism (n.): "mere parroting, parrotry, repetition without reasoning," 1884, from French psittacisme (Liebnitz, 1765) or German psittazismus, from Latin psittacus "parrot" (see psittacine) + -ism.
psoas (n.): 1680s, from Greek psoa (plural psoai) "muscles of the loins." Related: Psoitis.
Gk. [psoas], the gen. of the feminine noun [psoa], was mistaken by the French anatomist Jean Riolan (1577-1657) for the nom. of a (nonexistent) masculine noun. It was he who introduced this erroneous form into anatomy. [Klein]
psoriasis (n.): 1680s, from medical Latin psoriasis, in Late Latin "mange, scurvy," from Greek psoriasis "being itchy," from psorian "to have the itch," from psora "itch, mange, scab," related to psen "to rub" (see psilo-). Related: Psoriatic.
psych: as a noun, short for psychology in various senses (e.g. as an academic study, in student slang by 1895). As a verb, first attested 1917 as "to subject to psychoanalysis," short for psychoanalyze. From 1934 as "to outsmart" (also psych out); from 1963 as "to unnerve." However to psych (oneself) up is from 1972; to be psyched up is attested from 1968.
psyche (n.): 1640s, "animating spirit," from Latin psyche, from Greek psykhe "the soul, mind, spirit; breath; life, one's life, the invisible animating principle or entity which occupies and directs the physical body; understanding" (personified as Psykhe, the beloved of Eros), akin to psykhein "to blow, cool," from PIE root *bhes- "to blow, to breathe" (source also of Sanskrit bhas-), "Probably imitative" [Watkins].

Also in ancient Greek, "departed soul, spirit, ghost," and often represented symbolically as a butterfly or moth. The word had extensive sense development in Platonic philosophy and Jewish-influenced theological writing of St. Paul (compare spirit (n.)). Meaning "human soul" is from 1650s. In English, psychological sense "mind," is attested by 1910.
psychedelia (n.): 1967, from psychedelic + -ia.
psychedelic (adj.): occasionally psychodelic, 1956, of drugs, suggested by British-born Canadian psychiatrist Humphry Osmond (1917-2004) in a letter to Aldous Huxley and used by Osmond in a scientific paper published the next year; from Greek psykhe- "mind" (see psyche) + deloun "make visible, reveal," from delos "visible, clear," from PIE root *dyeu- "to shine" (see diurnal). In popular use from 1965 with reference to anything producing effects similar to that of a psychedelic drug or enhancing the effects of such a drug. As a noun from 1956.
psychedelicize (v.): 1966, from psychedelic + -ize. Related: Psychedelicized; psychedelicizing.
psychiatric (adj.): 1847, from French psychiatrique or else coined in English from psychiatry + -ic.
psychiatrist (n.): 1875, from psychiatry + -ist.
A psychiatrist is a man who goes to the Folies Bergère and looks at the audience. [Anglican Bishop Mervyn Stockwood, 1961]
An older name was mad-doctor (1703); also psychiater "expert in mental diseases" (1852), from Greek psyche + iatros. Also see alienist.
psychiatry (n.): 1846, from French psychiatrie, from Medieval Latin psychiatria, literally "a healing of the soul," from Latinized form of Greek psykhe- "mind" (see psyche) + iatreia "healing, care" (see -iatric).
psychic (adj.): 1872, "of or pertaining to the human soul" (earlier psychical, 1640s), from Greek psykhikos "of the soul, spirit, or mind" (opposed to somatikos), also (New Testament) "concerned with the life only, animal, natural," from psykhe "soul, mind, life" (see psyche). Meaning "characterized by psychic gifts" first recorded 1871.
psychic (n.): "a medium;" 1870; see psychic (adj.).
psycho (adj.): 1927, shortening of psychological; 1936 (Raymond Chandler) as shortening of psychopathic (adj.).
psycho (n.): 1925, short for psychologist; as short for psychopath from 1942.
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 psychapates "soul-beguiling" (with apate "deceit").
psycho-history (n.): 1934, from psycho- + history.
psychoactive (adj.): also psycho-active, 1959, from psycho- + active.
psychoanalysis (n.): 1906, from Psychoanalyse, coined 1896 in French by Freud from Latinized form of Greek psykhe- "mental" (see psyche) + German Analyse, from Greek analysis (see analysis). Freud earlier used psychische analyse (1894).
psychoanalyst (n.): also psycho-analyst, 1910; see psycho- + analyst.
psychoanalytic (adj.): 1902, from psychoanalysis + -ic.
psychoanalyze (v.): also psycho-analyse, psychoanalyse, 1911; see psycho- + analyze. Related: Psychoanalyzed; psychoanalyzing. Earlier was psychologize (1830).
psychobabble (n.): 1976, from psycho- (representing psychology) + babble (n.). Earlier was psychologese (1961).
psychodrama (n.): also psycho-drama, 1937 (in writing of U.S. psychiatrist Jacob L. Moreno (1889-1974)), from psycho- + drama. Related: Psychodramatic.
psychodynamic (adj.): also psycho-dynamic, 1856, from psycho- + dynamic (adj.).
psychogenesis (n.): also psycho-genesis, 1838, "origin of the soul or mind," from psycho- + -genesis "birth, origin, creation." Related: Psychogenetic; psychogenetical.
psychogenic (adj.): 1884, from psycho- + -genic.
psychographic (adj.): also psycho-graphic, 1856, from psychograph "supernatural photographic image," from psycho- + -graph. Related: Psychographics.
psychography (n.): 1883, "history of an individual soul; the natural history of the phenomenon of mind," from psycho- + -graphy. Meaning "spirit-writing" is from 1876.
psychokinesis (n.): 1914 [Henry Holt, "On the Cosmic Relations"], from psycho- + kinesis. Related: Psychokinetic (1904).
psychological (adj.): 1680s; see psychology + -ical. Related: Psychologically. Psychological warfare recorded from 1940. Psychological moment was in vogue from 1871, from French moment psychologique "moment of immediate expectation of something about to happen."
The original German phrase, misinterpreted by the French & imported together with its false sense into English, meant the psychic factor, the mental effect, the influence exerted by a state of mind, & not a point of time at all, das Moment in German corresponding to our momentum, not our moment. [Fowler]
psychologist (n.): 1727; see psychology + -ist.
psychology (n.): 1650s, "study of the soul," from Modern Latin psychologia, probably coined mid-16c. in Germany by Melanchthon from Latinized form of Greek psykhe- "breath, spirit, soul" (see psyche) + logia "study of" (see -logy). Meaning "study of the mind" first recorded 1748, from Christian Wolff's "Psychologia empirica" (1732); main modern behavioral sense is from early 1890s.
psychometric (adj.): also psycho-metric, 1854, from psychometry (1854), the alleged power of reading the history of an object by handling it, + -ic. In reference to the measurement of the duration of mental states, from 1879, from psycho- + -metric.
psychometrics (n.): "science of measuring mental processes," 1917, from psychometric; also see -ics.
psychomotor (adj.): also psycho-motor, 1873, from psycho- + motor (adj.).
psychopath (n.): 1885, in the criminal psychology sense, a back-formation from psychopathic.
The Daily Telegraph had, the other day, a long article commenting on a Russian woman who had murdered a little girl. A Dr. Balinsky prevailed upon the jury to give a verdict of acquittal, because she was a "psychopath." The Daily Telegraph regards this term as a new coinage, but it has been long known amongst Spiritualists, yet in another sense. ["The Medium and Daybreak," Jan. 16, 1885]
The case alluded to, and the means of acquittal, were briefly notorious in England and brought the word into currency in the modern sense.
psychopathic (adj.): 1847, from psychopathy on model of German psychopatisch, from Greek psykhe- "mind" (see psyche) + pathos "suffering" (see pathos).
psychopathology (n.): 1847, from psycho- + pathology, on model of German psychopathologie.
psychopathy (n.): 1847, from psycho- + -pathy, on model of German psychopathie.
psychopharmacology (n.): also psycho-pharmacology, 1919, from psycho- + pharmacology. Related: Psychopharmacological.
psychopomp (n.): 1835, from Greek psykhopompos "spirit-guide," a term applied to Charon, Hermes Trismegistos, Apollo; from psykhe (see psyche) + pompos "guide, conductor."
psychosexual (adj.): also psycho-sexual, 1891, from psycho- + sexual. Related: Psychosexually.
psychosis (n.): 1847, "mental derangement," Modern Latin, from Greek psykhe- "mind" (see psyche) + -osis "abnormal condition." Greek psykhosis meant "a giving of life; animation; principle of life."
psychosocial (adj.): also psycho-social, 1891, from psycho- + social (adj.).
psychosomatic (adj.): 1847, "pertaining to the relation between mind and body," from Greek psykhe- "mind" (see psyche) + somatikos, from soma (genitive somatos) "body" (see somato-). Applied from 1938 to physical disorders with psychological causes. Etymologically it could as easily apply to emotional disorders with physical causes, but it is rarely used as such.
psychotherapist (n.): 1894, from psychotherapy + -ist.