Terminology of Microtonal music

Microtonal music can refer to all music which contains intervals smaller than the conventional contemporary Western semitone. The term implies music containing very small intervals but can include any tuning that differs from the western 12-tone equal temperament.  The following systems are considered to be microtonal: the traditional Carnatic system of 22 sruti; much Indonesian gamelan music; Thai, Burmese, and African music using seven tones in each (approximate) octave; and blues and/or rock music which makes extensive use of blues notes. Also, music using just intonation, meantone temperament, or other alternative tunings may be considered microtonal.

Other terminology has been used (and is still used today) by theorists and composers. Micro-intervals is commonly used to speak about intervals smaller than the semitone, and sometimes macro-intervals for non-multiples of the semitone greater than it. Ivan Wyschnegradsky used the term ultra-chromatic for micro-intervals and infra-chromatic for macro-intervals (Wyschnegradsky 1972, 84-87). Ivor Darreg proposed the term xenharmonic (from the Greek ξένος, foreign, and Greek ξενία, hospitable) for any scale other than the 12-tone equal-tempered scale.
And these are some of microtonal composers