P-Plan is an OWL2 ontology developed to describe abstract scientific workflows as plans and link them to their past executions.

P-Plan extends the W3C PROV-O Ontology [PROV-O], which encodes the W3C PROV data model [PROV-DM]. PROV-DM describes the provenance of objects (prov:Entities) as a record of assertions about the steps (prov:Activities) that generated them and the entities used in those steps. Provenance describes past execution, but does not offer a vocabulary to express the plan that the execution was supposed to follow.