ὄv, ὄντα, on, onta (being, beings), 1, 3, 14, 90fn, 96fn, 138, 213 (BTJS)

But the problem lies deeper still. Why is it, after all, that ὄν ᾗ ὄν gives rise to the confusion in the first place? The reason, we are told, lies in the nature of ὄν itself. Grammatically, it is a participle and as such may be used either as a noun (v.g. can a human being live on the moon?) or as an adjective with a verbal sense (v.g. being curious, we want to know). More precisely: ὄν, when taken as a noun, means that which is, sc. a being (Seiendes); taken as a verbal adjective (seiend), it designates that process by which a being (as noun) “is,” sc. its Being (Sein). The word itself, then, comporting both senses, is intrinsically ambivalent, and it is because ὄν itself can mean either Being, or beings, or both, that the interrogation of ὄν ᾗ ὄν can evolve as a meditation on either Being-in-general (ontology) or on the ultimate ground (theology). In other words, the ontotheological structure of metaphysics is rooted ultimately in the intrinsic ambivalence of ὄν.

It would be a grave mistake, however, to think that this ambivalence of ὄν is something peculiar to Aristotle. The fact is that it characterizes the entire history of Greek thought. The primitive form of ὄν, Heidegger claims, is most probably ἐόν, as the word is found, for example in Homer (v.g. Iliad, I, 70), or even in Parmenides and Heraclitus. (RHPT:10-11)