metaphysics

n.pl. (usu. Treated as sing.) 1 branch of philosophy dealing with the nature of existence, truth, and knowledge. 2 colloq. Abstract talk; mere theory. [greek, as having followed physics in aristotle's works]

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.