Hypostasis

Hypostasis (“that which stands beneath,” underlying reality) came to name, in Neoplatonism, a genuine level of being — a real existent rather than a mere aspect or appearance.

In Plotinus the term marks the three primary realities of the Enneads: the One, Intellect, and Soul — each proceeding from the one before it and turning back toward it in contemplation. The word would later pass into Christian theology, pressed into the service of trinitarian and christological debate.