The Knowledge Graph is a structured database or network of interconnected entities (nodes) and relationships (edges) representing real-world facts. It is conceptually based on an ontology, which defines the underlying schema and organizing principles. The KG is crucial for enabling semantic search, solving ambiguity issues, providing Knowledge Panels, and grounding generative AI for question-answering applications. The KG is regularly updated via a reconciliation process by finding and adding missing entities and relationships. Search engines leverage the KG to refine and augment queries, moving the search process toward a more entity-centric understanding.