That which STANDS UNDER — hypo, 'under', + stasis, 'a standing': the underlying reality, substance or ground of a thing. ⚠ It has two New Testament lives: at Hebrews 1:3 it means God's REAL BEING, of which the Son is the exact imprint; at Hebrews 11:1 the sense is genuinely open — 'faith is the hypostasis of things hoped for', which the versions render as OBJECTIVE substance (KJV, RV 'sustancia'), SUBJECTIVE assurance (ASV, TNM 'certeza'), or NWT's hybrid 'assured expectation'; and in the Greek commercial papyri the same noun is a TITLE-DEED, the document proving you own what you cannot presently see, which may be the sharpest option of all. The word occurs five times in the New Testament. ⚠ And it became the single most fought-over term of the fourth-century Trinitarian debates: the church settled on three hypostaseis (Father, Son and Spirit) in one ousia (being) — but for a long time hypostasis and ousia were used as synonyms, and the confusion nearly wrecked the councils. Latin rendered it substantia and then persona, which is why the KJV reads 'person' here. → first discussed at Hebrews 1:3