Canon
Multi-voice form in which all voices perform the same melody offset in time.
What it means
The canon is a multi-voice musical form in which all participating voices sing or play the same melody but each enters offset in time. While the first voice to enter proceeds, the next begins from the start, so that when different sections of the melody sound simultaneously, harmonies result that the composer must have planned in advance.
Musical use
Canons range from simple forms meant for communal singing, such as “Frère Jacques,” to artful, strictly constructed compositions, for instance in Johann Sebastian Bach's Musical Offering or Goldberg Variations. The canon is also a compositional technique: special forms such as the crab canon, in which one voice performs the melody backward, or the double canon with two simultaneous canons, show the variety of the principle.
The canon should be distinguished from imitation in the wider sense, which can concern only a section, whereas the canon strictly sustains the imitation through the whole piece. It differs from the fugue in that in a canon all voices continuously repeat the same theme in the same shape, whereas the fugue works with episodes and freer voice leading.
Performance practice
Sing or play a canon alone first to master the melody securely before entering together with other voices. When singing together, listen closely to the other entries so that your own entry fits exactly in time and the resulting harmonies sound clean.