An ontology describes the things in a system and the relationships between them. By relationships, I don't just mean A is related in some way to B, I mean (for

An ontology describes the things in a system and the relationships between them. By relationships, I don't just mean A is related in some way to B, I mean (for example) A modifies B, or A requires B, or even A eats lunch with B. In short, they relate things to each other using whatever the verbs in that domain are. Imagine a database schema, but with richer information. In theory, if you have a good ontology, you can translate an expert human's understanding of a system to something a computer can also understand. So if, for example, you were going to write software to orchestrate the production of a massive film, or a commercial production studio, you might benefit from a common ontology for film production. In practice, ontologies in the wild have had limited success, historically, compared to expectations in the academic world around the end of the last century.