Ontology
Etymology
From Greek "on," "ontos," "being," plus "logos," "study of." The word was coined in the early 1600s by scholars such as Jacob Lorhard and Rudolf Goclenius and later systematized by Christian Wolff. In computing it has taken on a second life, meaning a formal map of the entities in some domain and how they relate.
noun · /on-TOL-uh-jee/
The branch of philosophy that studies what exists and what it means for something to be — the basic categories of reality.
What it names
A handle for the deep question hiding under everyday disputes: are numbers, minds, corporations, or laws real things, or just useful fictions?
Example
Whether a corporation can “want” anything is an ontology question: it asks what kind of thing a corporation even is.
Related idea
Metaphysics is the broader field that asks about the nature of reality generally; ontology is the sharper sub-question of what specifically exists.