Definition of: metaphysics

(met′ə·fiz′iks) noun plural (construed as singular)
1. The systematic study or science of the first principles of being and of knowledge; the doctrine of the essential nature and fundamental relations of all that is real.
2. Speculative philosophy in the wide sense.
3. The principles of philosophy as applied to the methodology of any particular science.
4. Mental science in general; psychology.
5. In popular use, abstruse and bewildering discussion. Also metaphysic. [<Med. L metaphysica <Med. Gk. <ta meta ta physika the (works) after the physics; in ref. to Aristotle's ontological treatises, which came after his Physics]