Multiple online services host repositories of audio clips of different kinds, ranging from music tracks, albums, playlists, to instrument samples and loops, to a variety of recorded or synthesized sounds. Programmatic access to these resources maybe used by client applications for tasks ranging from customized musical listening and exploration, to music/sounds creation from existing sounds and samples, to audio-based user interaction in apps and games. To facilitate interoperability among repositories and clients in this domain, we designed an ontology that covers it. There was no previous comprehensive data model for this domain, however the new ontology relates to existing ontologies such as the Functional Requirements for Bibliographic Records for the authoring and publication process of creative works, the Music Ontology for the authoring and publication of music, the EBU Core ontology to describe media files and formats, the Creative Commons Licensing ontology to describe licences. This paper documents the design of the ontology and its evaluation in respect to the requirements and scope.