- Metrical rhythm in which every time value is a multiple or
fraction of a fixed unit of time, called beat, and in which the
normal accent recurs in regular intervals, called measure.
The basic scheme of time values is called meter.
- Measured rhythm which lacks regularly recurrent accent. In
modern notation such music appears as a free alternation of different
- Free rhythm, i.e., the use of temporal values having no common
metrical unit (beat).