A baseline is an approved configuration item , e.g. a project plan that has been signed off for execution.

In configuration management, no single consistent definition of baseline (configuration management) exists. Authoritative sources vary in their explanation. The precise meaning also varies upon context, where in some uses (particularly in conversation) the term is referred to as an activity, so as to establish configuration item (s) for a particular purpose, meeting certain criteria. This sense is also used in the past tense form, "the document was baselined." In other circumstances, especially academically and leveraged in practice, the term is a noun describing the state of an entity or entities captured at a moment in time whereby subsequent changes are permitted only upon formal approval. This latter sense of the term is the focus of numerous variations in that it may refer to a specific version in the history of a single work product, or a set of numerous work products at a given point in time associated with a public approval status.