ontology
study of the nature of being, becoming, existence or reality, as well as the basic categories of being and their relations (philosophy)
Identity and change
ontology
Stoic categories
Stoic classification of all beings into substance (ὑποκείμενον), quality (ποιόν), somehow disposed (πως ἔχον), or somehow disposed in relation to something (πρός τί πως ἔχον)
Unified Medical Language System
medical informatics tool
object-oriented ontology
metaphysical theory