Hyparxis (Greek, ὕπαρξις) means "essential nature" and is the Neoplatonic term for the summit, beginning, or hierarch of a hierarchy, as follows:

• The word is particularly used by the Neoplatonist, Proclus who uses it to mean "the summit of any nature, or blossom, as it were, of its essence." Thus, for example: "But others, suspending indeed all bodies from incorporeal natures, and defining the first hyparxis to be in soul, and the powers of soul, call (as appears to me) the best of souls, Gods; and denominate the science which proceeds as far as to these, and which knows these, theology. But such as produce the multitude of souls from another more ancient principle, and establish intellect as the leader of wholes, these assert that the best end is a union of the soul with intellect, and consider the intellectual form of life as the most honorable of all things." Proclus, On the Theology of Plato, trans. by Thomas Taylor, Ch. III, 1st para.
• "Now the Neo-Platonists who first came into prominence in the early centuries of the Christian era and who, with the Stoics, provided Christianity with all that it had that was philosophically good and spiritual and true taught that the summit, the acme, the flower, the highest point (that they called the "hyparxis") of any series of animate and "inanimate" beings, whether we enumerate the stages or degrees of the series as seven or ten or twelve (according to whichever system we follow), was the "divine unity "for that series or Hierarchy, and that this hyparxis or flower or summit or beginning or highest being was again in its turn the lowest being of the Hierarchy above it, and so extending onwards for ever." Gottfried de Purucker, Fundamentals of the Esoteric Philosophy, ed. by A. Trevor Barker, (London: Rider & Co., 1932), p. 55.
• Equivalent to the First Logos.^[1]

But in the Bible, specifically the New Testament, it also means "goods possessed, substance, property" as in the following:

• Acts 2:45 - "and they were selling their possessions and belongings (hyparxeis | ὑπάρξεις | acc pl fem) and distributing the proceeds to all, as anyone had need."
• Hebrews 10:34 - "for in fact you shared the sufferings of those in prison, and with joy accepted the confiscation of your belongings, since you knew that you yourselves had a better and lasting possession (hyparxin | ὕπαρξιν | acc sg fem)." ^[2]