- A package is a ZIP archive (.zip, .rez) which contains a set of media files and typically one compilation. The tracks reference to the media files.
- A compilation is a set of tracks, usually representing a playlist for a concert or rehearsal session. Compilations are stored as XML files (.xml, .rex), either within packages or as standalone files.
- A track represents a single media file and a set of cues for it. Within a compilation, more than one track may reference the same media file, to simplify rehearsal variants e.g. for different voices (SATB) or parts in large pieces.
- A media file is a binary file, containing playable music. A variety of audio formats are supported, both from the local file system and via an online URL.
- A cue represents a named temporal position in a track. A cue can have a (keyboard) shortcut.
- A shortcut is a short mnemonic for a cue, to speed up navigation within a track or compilation, using a keyboard.