Official definition: A knowledge graph is a graph-based data structure consisting of nodes (points) and edges (Edges). Each node represents an "entity", and each edge is a "relationship" between entities and entities. Graphs are essentially semantic networks.
Entities can refer to things in the real world, such phone number list as people, place names, companies, telephones, animals, etc.; relationships are used to express a certain connection between different entities.
From the above picture, we can see that entities have place names and people; Dali belongs to Yunnan, Xiaoming lives in Dali, Xiaoming and Xiaoqin are friends, these are the relationships between entities.
Popular definition: A knowledge graph is a relational network obtained by connecting all different kinds of information, so the knowledge graph provides the ability to analyze problems from the perspective of "relationship".
2. Visual performance
If we search for "Jay Chou's wife" on Baidu, the search result is not Jay Chou, but directly returns Kun Ling's information card, why?
Because the underlying knowledge graph already has a relationship between Jay Chou and Kun Ling, it is understandable that you are looking for Kun Ling, not Jay Chou, which also shows that the knowledge graph has the ability to understand user intent.