hy·pos·ta·sis 
(hī-pŏstə-sĭs)
(hī-pŏstə-sĭs)n. pl. hy·pos·ta·ses (-sēz′)
1. Philosophy The substance, essence, or underlying reality.
2. Christianity
a. Any of the persons of the Trinity.
b. The essential person of Jesus in which his human and divine natures are united.
3. Something that has been hypostatized.
4.
a. A settling of solid particles in a fluid.
b. Something that settles to the bottom of a fluid; sediment.
5. Medicine The settling of blood in the lower part of an organ or the body as a result of decreased blood flow.
6. Genetics A condition in which the action of one gene is concealed or suppressed by the action of an allele of a different gene that affects the same part or biochemical process in an organism.
[Late Latin, from Greek hupostasis : hupo-, hypo- + stasis, a standing; see stā- in the Appendix of Indo-European roots.]
hy′po·static (hī′pə-stătĭk), hy′po·stati·cal adj.
hy′po·stati·cal·ly adv.