Psȳ-chŏl'o-gy, n.

(sī-kŏl'o-jȳ), n. [Fr. psychologie, It. & Sp. psicologia, from Gr. ψυχή, the soul, mind, and λόγος, discourse.] A discourse or treatise on the human soul; 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.

I defined psychology, the science conversant about the phenomena of the mind, or conscious subject, or self, or ego. Sir W. Hamilton.