imitation

In music, a contrapuntal device in which a theme or motif is repeated in different vocal or instrumental parts. The strictest form of imitation is the canon, in which every voice has, in turn, exactly the same notes and rhythms as the one before it. In a fugue the subject (principal melody) is treated imitatively, before a greater degree of contrapuntal freedom occurs in a non-thematic episode (a passage linking appearances of the subject). The use of imitation in composition can be traced back to early forms of polyphony from about 1200.