What defines a canon in music?

A canon in music is characterized by a style in which multiple voices or instruments play the same melody starting at different times, thereby creating a layered effect. This technique involves imitation, where one voice leads, and subsequent voices enter with the same melody, creating harmonies and a rich textural experience.

This definition aligns perfectly with the concept of a canon, as it emphasizes the interactive and imitative nature of the voices involved in the piece. The result is a structured musical form that demonstrates both unity and independence among the parts.

The other options do not capture the essential qualities of a canon. A single melody played repeatedly refers more to an ostinato rather than the imitative character of a canon. A rhythm pattern repeated throughout a piece does not emphasize melody or voice interplay, which are crucial to the definition of a canon. A harmonic structure of chords describes tonal frameworks and progressions but does not directly tie into the concept of imitation central to canon writing. Therefore, the identification of a canon as a style where voices imitate a leading voice accurately reflects its musical function and characteristics.