1. an art of sound in time that expresses ideas and emotions in significant forms through the elements of rhythm, melody, harmony, and color.
2. the tones or sounds employed, occurring in single line (melody) or multiple lines (harmony), and sounded or to be sounded by one or more voices or instruments, or both.
3. musical work or compositions for singing or playing.
4. the written or printed score of a musical composition.
5. such scores collectively.