met·a·phys·ics 
(mĕt′ə-fĭzĭks)
(mĕt′ə-fĭzĭks)n.
1. (used with a sing. verb) Philosophy The branch of philosophy that examines the nature of reality, including the relationship between mind and matter, substance and attribute, possibility and actuality.
2. (used with a pl. verb) The theoretical or first principles of a particular discipline: the metaphysics of law.
3. (used with a sing. verb) A priori speculation upon questions that are unanswerable to scientific observation, analysis, or experiment.
4. (used with a sing. verb) Excessively subtle or recondite reasoning.
[From pl. of Middle English methaphisik, from Medieval Latin metaphysica, from Medieval Greek (ta) metaphusika, from Greek (Ta) meta (ta) phusika, (the works) after the Physics, the title of Aristotle's treatise on first principles (so called because it followed his work on physics) : meta, after; see META- + phusika, physics; see PHYSICS.]