in music, use of specified instruments to mark off established time intervals. In the tuned percussion ensembles ( gamelan) of Java and Bali, for instance, a musical unit of 16 measures may be marked by four instruments: a small gong striking once every odd-numbered measure; a larger gong striking each 4th, 8th, 12th, and 16th measure; another gong striking each 6th, 10th, and 14th; and the large gong ageng sounding in the 16th.

Other examples of colotomic structure occur in the gagaku, or court music, of Japan (two- and four-measure divisions marked by a drum and hanging gong) and in the pi phat (percussion and oboe) ensembles of Thailand.