- id (n.) 1924, in Joan Riviere's translation of Freud's "Das Ich und das Es" (1923), from L. id "it" (translation of Ger. es "it" in Freud's title), used in psychoanalytical theory to denote the unconscious instinctual force. Latin id is from PIE pronomial stem *i- (see YON (Cf. yon)).
Etymology dictionary. 2014.