diapason

 
Pronunciation: /ˌdʌɪəˈpeɪs(ə)n, -z-/

noun

  • 1 (also open diapason or stopped diapason) an organ stop sounding a main register of flue pipes, typically of eight-foot pitch.
  • 2a grand swelling burst of harmony.
  • 3 literary the entire compass, range, or scope of something.

Origin:

late Middle English (denoting the interval of an octave): via Latin from Greek dia pasōn (khordōn) 'through all (notes)'