Noun
half of a semitone
Source: WordNetquarter-tone
These "moderns" were discarding the old laws of composition and experimenting with new forms, harmonies and rhythms, and including the use of jazz and quarter-tone music. Source: Internet
Various composers including Charles Ives experimented with music for quarter-tone pianos. Source: Internet
For instance, three pure major thirds stack up to 125/64, which at 1158.94 cents is nearly a quarter tone away from the octave. Source: Internet
Arabic music maqamat may use quarter tone intervals. Source: Internet
Thus, the first and third valves used in combination lower the pitch by something just short of five semitones, and the first three valves used in combination are nearly a quarter tone sharp. Source: Internet
Some instruments feature a fourth valve that provides a quarter-tone step between each note. Source: Internet