Full Idea
On any interpretation, Aristotle argues that primary being with regard to each thing is both the essence of that thing and the ultimate subject of predication with regard to that thing.
Gist of Idea
Primary being is both the essence, and the subject of predication
Source
report of Aristotle (Metaphysics [c.324 BCE], ousia) by Vassilis Politis - Aristotle and the Metaphysics 7.5
Book Reference
Politis,Vasilis: 'Aristotle and the Metaphysics' [Routledge 2004], p.228
A Reaction
This is Politis's prelude to an account of conflicting interpretations over whether 'ousia' has one or two meanings for Aristotle.