Microtones

They are intervals smaller than a semitone.

In Indian music theory, they are called shruti (not to be confused with the Vedic shruti).

References: https://www.wisdomlib.org/definition/shruti
https://thoughts4ideas.eu/shruti-and-svara/
https://medium.com/@monicajoshi_26785/shruti-shravan-anatomy-of-shruti-in-indian-classical-music-83f4ddcddc48

Non-Western music includes mircotones: https://www.huygens-fokker.org/microtonality.html

Much non-Western music is microtonal: classical music from India, Turkey, Arabia and Persia, gamelan music from Indonesia, xylophone music from Africa, Byzantyne liturgical music, folk music from Middle- and Eastern Europe, the Caucasus, etc.

Shruti is the interval or step, while Swara is the specific note or pitch.
Some say shruti is the octave. Generally, I think it means the key.
Svara also refers to the solfege of the Carnatic music system.

There are 22 shrutis in Hindustani music, but 12 are more prominently used and are called musical notes.
The Carnatic music system has 24, with influence from Arabic music.