A knowledge graph is a graph structure in which source entities are linked to target ones through directed and labeled edges.

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), Vol.9924, pp.28-36 [Peer Reviewed Journal] 2016 [Constraint-Based Open-Domain Question Answering Using Knowledge Graph Search]

Knowledge graph acquires and integrates information in an ontology and applies a reasoner to derive new knowledge.

Lisa Ehrlinger and Wolfram Wöß. 2016. Towards a Definition of Knowledge Graphs. In Joint Proceedings of the Posters and Demos Track of the 12th International Conference on Semantic Systems - SEMANTiCS2016 and the 1st International Workshop on Semantic Change & Evolving Semantics (SuCCESS’16), Michael Martin, Martí Cuquet, and Erwin Folmer (Eds.), Vol. 1695. CEUR-WS, Leipzig, Germany. [CEUR-WS]