Realizable entities are properties that can be realized in processes of specific correlated types in which the bearer participates. It will be valuable to create a systematic classification of realizable entities because they are useful for various modeling purposes in ontologies. In this paper we outline a unifying framework for realizable entities (including dispositions and roles) in the upper ontology Basic Formal Ontology (BFO) that is theoretically underpinned by J. McKitrick’s pragmatic approach to dispositions. In particular, we develop a formal ontological account of “extrinsic dispositions” and illustrate its potential applications with clarification of functions and roles in BFO.