Abstract
In this paper I discuss the different senses in which Plotinus uses the word 'ousia', a word crucial for ancient metaphysics. By means of discussing these senses, it becomes apparent how Plotinus answers the central question of any metaphysical theory: what is being? It turns out that his layered ontology gives a number of different but conceptually linked answers to this question, each reflecting one use of the term 'ousia'. In a kind of "ascent" bodies, the soul, and the intellect are considered as different ways of being.