A knowledge graph is a structured representation of information that connects various entities, such as people, places, and things, through relationships. It organizes data in a way that makes it easier for computers to understand and process, allowing for better search results and insights. These graphs use nodes to represent entities and edges to illustrate the relationships between them. For example, a knowledge graph might show that Albert Einstein is a physicist who was born in Ulm, Germany. This interconnected data helps in applications like search engines and recommendation systems.