The interaction concept has been given much importance in computer science and information systems. The interactions happen at different levels and in different situations. Interactions involve actors that act in re-action to one other action. The enterprise, as an actor, needs to implement interactions. Indeed, the knowledge emerging from interactions is greater than the sum of the involved actor’s knowledge. Traditionally, interactions are implemented on a case-by-case basis without managed view, which yields costly integration architectures, because they do not consider the semantic aspect of the interactions. Ontology is the solution for the semantic problem, which provides a smooth integration. This paper aims at building Ontology for enterprise interactions, specifically Extended Enterprise (EE) and Virtual Enterprise (VE), whereby an EE is a kind of collaboration between loosely coupled enterprises that combine their economic output to provide product/service offerings. An EV is a temporary relationship between distributed enterprises, competitors, and partners which access each other market.