A Hypostasis

1. (medicine, now historical) A sedimentary deposit, especially in urine. [from 14th c.]
2. (theology) The essential person, specifically the single person of Christ (as distinguished from his two ‘natures’, human and divine), or of the three ‘persons’ of the Trinity (sharing a single ‘essence’). [from 16th c.]
3. (philosophy) The underlying reality or substance of something. [from 17th c.]
4. (genetics) The effect of one gene preventing another from expressing. [from 20th c.]
5. Postmortem lividity; livor mortis; suggillation.

subsistence