An ontology is a study of a thing’s existence, how it exists in relation to other things that exist.
Ontology is looking at yourself in the mirror and asking, “Do I exist? How do I exist? How do I know that I exist? Am I an indivisible whole or am I set of components? Is my whole a component of some larger whole?”
Ontology is an extremely broad field in metaphysics and philosophy.
Easy way to remember what ontology means?
A paleontologist searches for bones to find out if something existed. Then studies the bones to find out how that thing existed.