(1):

(n.) That which forms the basis of anything; underlying principle; a concept or mental entity conceived or treated as an existing being or thing.

(2):

(n.) Substance; subsistence; essence; person; personality; - used by the early theologians to denote any one of the three subdivisions of the Godhead, the Father, Son, and Holy Spirit.

(3):

(n.) Principle; an element; - used by the alchemists in speaking of salt, sulphur, and mercury, which they considered as the three principles of all material bodies.

(4):

(n.) That which is deposited at the bottom of a fluid; sediment.