Definition of quarter-tone in English:

quarter-tone

noun

Music
  • Half a semitone.

    • ‘He would insert folk tunes into his exercises or submit pieces with free rhythms, quarter-tones and multilayered textures.’
    • ‘The two instruments are tuned a quarter-tone apart, and it's incredible how soon the ear becomes accustomed to the strangeness of this tuning.’
    • ‘Mirage was written in 1910, and inhabits - quarter-tones aside - the soundworld of Wagner, with a nod towards the tone poems of Richard Strauss.’
    • ‘Downie's contribution is not all quarter-tones and ululations, though.’
    • ‘While making a direct comparison, I discovered that the original UK vinyl edition must have been mastered at the wrong speed, since it plays a quarter-tone below the CD version.’

Pronunciation:

quarter-tone

/ˈkwôrdər ˌtōn/