Hy*pos"ta*sis (?), n.; pl. Hypostases (#). [L., fr. Gr. subsistence, substance, fr. to stand under; under + to stand, middle voice of to cause to stand. See Hypo-, and Stand.]
That which forms the basis of anything; underlying principle; a concept or mental entity conceived or treated as an existing being or thing.
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.
⇒ The Council of Alexandria (a.d. 362) defined hypostasis as synonymous with person.
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.
That which is deposited at the bottom of a fluid; sediment.
© Webster 1913.