A shared model for concepts, relationships, and rules in a knowledge system.
Ontology is like a bossy grocery-store map. Milk is dairy. Socks are not fruit.
You meet it in knowledge bases, search, and Q&A. It lines up data, so rules can make sense.
KR
Ontology is a KR method for concepts and relationships.
Knowledge Graph
An ontology keeps a Knowledge Graph's nodes, links, and meanings consistent.
RAG
Ontology helps RAG find the right sources more often.
DL
DL is often used to write ontology rules in a formal way.