In Metaphysics, that stuff which underlies objects observable by the senses.

That which has or gives rise to the observable properties of “whereness” (i.e., space), “whenness” (i.e., time), “whyness” (i.e., causation), and “whatness” (i.e., extension, mass, motion, number).

One of Aristotle’s four causes of things.

The stuff which Materialists claim is the sole type of existing substance from which everything that exists is made.