Ontology

Originally a philosophy term about "the system of what exists," but in IT it means a map that organizes a field's concepts and their relationships so computers can work with them. It's a blueprint that connects concepts as dots (nodes) and relationships as lines — like "OpenAI —creates→ GPT" and "GPT —is built into→ ChatGPT."

When this blueprint is filled with actual data, it's called a Knowledge Graph. The info box that pops up on the right when you search for a person on Google is a classic example — it's not pulling from a document, but retrieving from a pre-organized network of relationships.

There's a reason ontology is getting renewed attention in the LLM era. Language models sound plausible but can get facts wrong (hallucination), while ontologies are the opposite — because relationships are explicit, they don't go wrong. So there are ongoing efforts to combine "the fluency of LLMs with the accuracy of knowledge graphs." METAL also runs an ontology that places articles on top of company, model, and paper nodes — rather than as standalone pieces — and this is what powers the "articles mentioning this term" section in this dictionary and the related-article links at the bottom of each piece.

"They combined it with a knowledge graph to catch hallucinations" — a common phrase in articles about enterprise AI adoption, referring to a structure that pairs a fluent LLM with an accurate relationship network.

1. Try telling a chatbot: "Take these six as nodes and map out the relationships with arrows: OpenAI, GPT, ChatGPT, Microsoft, NVIDIA, GPU."
2. You'll get a map with relationship labels like "creates," "is built into," "invests in," and "supplies" — what you just made is a mini knowledge graph.
3. One step further: paste in any AI news article and ask, "Extract the companies, products, and people in this article as nodes, and the relationships as lines." Once the article starts to look like one piece of a larger relationship network — that's exactly why media outlets and companies build ontologies.