hypostasis

noun (plural hypostases /-siːz/)

• 1 [mass noun] Medicine the accumulation of fluid or blood in the lower parts of the body or organs under the influence of gravity, as occurs in cases of poor circulation or after death.

• 2 Philosophy an underlying reality or substance, as opposed to attributes or to that which lacks substance.

• 3 Theology (in Trinitarian doctrine) each of the three persons of the Trinity, as contrasted with the unity of the Godhead.
• [in singular] Theology the single person of Christ, as contrasted with his dual human and divine nature.