Hypokeimenon (Greek: ὑποκείμενον), later often material substratum, is a term in metaphysics which literally means the "underlying thing" (Latin: subiectum).

Hypokeimenon (Greek: ὑποκείμενον), later often material substratum, is a term in metaphysics which literally means the "underlying thing" (Latin: subiectum).