In this paper, we describe the ontology of drama called Drammar. Pervasive in old and new media, and relevant from a multi-disciplinary perspective that ranges from literary criticism and semiotics to aesthetics and psychology, the manifestations of drama are ubiquitous in today's culture, overcoming the boundaries of genres and formats. Drawing from an extensive survey of the literature on drama, Drammar formalizes the elements of drama in a media-and task-independent way. Drammar is encoded in OWL2 to provide an interoperable formal model for representing and studying drama in a variety of systems. Issued by a research initiative carried out in an interdisciplinary way over a decade, Drammar abstracts from the media and languages by which drama is conveyed, providing a formal systematization of the core notions about drama that leverages the theories and models of agency in the tradition of Artificial Intelligence. In this paper, we illustrate the ontology, describing its design and motivations through examples and use cases.