/huy pos"teuh sis, hi-/ , n. , pl. hypostases /-seez'/ .
1. Metaphys.
a. something that stands under and supports; foundation.
b. the underlying or essential part of anything as distinguished from attributes; substance, essence, or essential principle.
2. Theol.
a. one of the three real and distinct substances in the one undivided substance or essence of God.
b. a person of the Trinity.
c. the one personality of Christ in which His two natures, human and divine, are united.
3. Med.
a. the accumulation of blood or its solid components in parts of an organ or body due to poor circulation.
b. such sedimentation, as in a test tube.
[ 1580-90; hypóstasis that which settles at the bottom; substance, nature, essence, equiv. to hypo- HYPO- + stásis standing, STASIS ]