Webster's Revised Unabridged Dictionary (1913 + 1828)
result(s) from the 1913
Psy*chol"o*gy (?), n. pl. Psychologies (). [Psycho- + -logy: cf. F. psychologie. See Psychical.] The science of the human soul; specifically, the systematic or scientific knowledge of the powers and functions of the human soul, so far as they are known by consciousness; a treatise on the human soul.
Psychology, the science conversant about the phenomena of the mind, or conscious subject, or self.
Sir W. Hamilton.