A canon is a piece of music in which the tune is played by different parts starting at different times. A round, such as ‘London Bridge is Falling Down’, is a type of canon!

Canons can be vocal and instrumental pieces. A ‘strict canon’ means the second part copies the first part exactly, whereas in a ‘free canon’ the parts can move away from each other.

In canons by J. S. Bach, the voices sometimes enter at different pitches and play the same tune backwards or upside down – this is called inversion!