(1):

(n.) The science of real as distinguished from phenomenal being; ontology; also, the science of being, with reference to its abstract and universal conditions, as distinguished from the science of determined or concrete being; the science of the conceptions and relations which are necessarily implied as true of every kind of being; phylosophy in general; first principles, or the science of first principles.

(2):

(n.) Hence: The scientific knowledge of mental phenomena; mental philosophy; psychology.