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.
- astonish
- astonished
- astonishing
- astonishingly
- astonishment
- Astoria
- Astor, John Jacob
- a storm in a teacup
- Astor, Nancy
- (as) tough as nails
- astound
- astounding
- astoundingly
- astraddle
- Astraea
- astragal
- astragalus
- astragate
- a straight face
- a straight fight
- astrakhan
- astral
- astral plane
- astral projection
- astrantia