For more than two decades, cluster theory has served as a basis for widespread implementation of regional development policies in several countries. However, there are still persistent struggles in academia towards agreement on clear operational definitions of a cluster. In this article, we argue that this definitional haziness, reflected by difficulties in demarcating the scale and scope of clusters, leads to a stretching of the cluster concept when put into practice. We show how actors, through cluster projects, are utilizing strategies of "hubbing" and/or "blending" to develop their own understandings of both what clusters are and what they might or should be. Through studies of three Norwegian cluster projects, we argue that national cluster policies, through translation of an academically vague concept, facilitate a stretching of the original definition of clusters, giving regional stakeholders leeway to integrate other theoretical rationales instead. We argue that this is not taken into account in current policies.