Knowledge Graph
A knowledge graph is a database of things and how they connect.
Picture a web of dots and lines, not a chart with bars.
Each dot is a person, place, company, or idea. Each line says how two of them are related.
Knowing that Marie Curie exists is not enough. A knowledge graph also stores that she was born in Warsaw, discovered radium, and won the Nobel Prize twice. Each fact is a link between two things.
That is how AI answers hard questions. It follows the links between facts instead of matching keywords.
Google runs one of the biggest, and it powers Knowledge Panels, featured snippets, and AI search overviews. Bing, Apple, Amazon, and the big AI labs run their own.