The Standard Music Description Language (SMDL), an application of the HyTime Hypermedia/Time-based document structuring facilities, is described. The discussion covers the domains of information that SMDL associates with any piece of music, the timing of cantus events, pitch in cantus events, gamut-based pitches, just-intoned pitches, user-defined functions for pitches, chords and chord symbols, instrumental and vocal sounds, and nonwestern music.<>