Topics range from species counterpoint through post-tonal and beyond. See also the Dictionary of Digital Media.

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- Madrigal
- Madrigalism
- Major interval
- Major scale
- Major triad
- Mass
- Mastering
- Master use license
- Matrix (12-tone)
- Mechanical license
- Mechanical rights organization
- Mechanical royalties
- Mediant
- Melodic interval
- Melodic minor scale
- Mensurstriche
- Meter
- Microtone
- Middle 8
- Middle entries
- MIDI
- Minimalistic music
- Minor interval
- Minor triad
- Minuet and trio form
- Missa brevis
- Mix
- Mixer
- Modal
- Modal mixture
- Modes
- Modes of limited transposition
- Modulation
- Moll
- Monitor
- Monody
- Motet
- Multiphonics
- Musica ficta
- Music publisher
- Musique concrète