A knowledge base is a form of database where the facts and rules of captured knowledge are stored. This might be network-based, frames or soem form of formal logic. As well as storage, the knowledge base needs suitable organisation and indexing to support reasoning.
Used in Chap. 2: pages 13, 16, 19, 22, 23; Chap. 6: page 82; Chap. 16: page 243; Chap. 18: page 277