In music, a time scale is specification of divisions (scale) of time or rhythm.
Curtis Roads (2001, p.3-4) distinguishes nine time scales of music:
1. Infinite: literally infinite, such as the length of sine waves in classical Fourier analysis,
2. Supra: months, years, decades, and centuries; everything above the level of
3. Macro: "overall musical architecture or form" or the level of the individual piece; minutes, hours, or even days,
4. Meso: "Divisions of form" including movements, sections, phrases; seconds and minutes,
5. Sound object (Schaeffer 1959, 1977): "a basic unit of musical structure" and a generalization of note (Xenakis' ministructural time scale); fraction of a second to several seconds,
6. Micro: "sound particles" (see granular synthesis) down to the threshold of audible perception; thousands to millionths of seconds,
7. Sample: sample (music), measured as are samples in millionths of a second or microseconds,
8. Subsample: changes "too brief to properly recorded or perceived", billionths of a second, nanosecond, or less, and
9. Infinitesimal: literally "infinitely brief" such as delta functions.
from “Microsound” 2001 Roads, Curtis