in music, the division of a time value (duration) into equal parts.
The fundamental types are the division of a note into two parts (a whole note into two half notes, a half note into two quarter notes, a quarter note into two eighth notes, and so forth) and the division of a note into three parts (a dotted whole note into three half notes, a dotted half note into three quarter notes, and a dotted quarter note into three eighth notes, for example). In addition, in musical composition the basic durations may be arbitrarily (conditionally) divided into equal parts that do not conform to the principle of division prevailing in a particular work. This type of rhythmic division gives rise to duplets, triplets, and quadruplets, quintuplets, sextuplets, septuplets and other groups of notes with many fractional durations, for which there are no specific terms.