— diapasonal , adj.
/duy'euh pay"zeuhn, -seuhn/ , n. Music.
1. a full, rich outpouring of melodious sound.
2. the compass of a voice or instrument.
3. a fixed standard of pitch.
4. either of two principal timbres or stops of a pipe organ, one of full, majestic tone (open diapason) and the other of strong, flutelike tone (stopped diapason) .
5. any of several other organ stops.
6. a tuning fork.
[ 1350-1400; ME diapasoun diapason the whole octave dià pasôn ( chordôn ) through all (the notes), short for he dià pasôn chordôn symphonía the concord through all the notes of the scale ]