Ontology is what a knowledge community technology needs to know about, and how those things relate to one another. The domain has a scope. A Good Ontology is a Language, a graph (mathematical Object), and a model of reality.

Ontology in AI provides a web of concepts so that AI can "understand" the data it processes.

https://youtu.be/UW57RW-4kWs?si=anbbqbjCDNUQNRyN&t=183