diapason

Etymology

Borrowed from Latin diapason, from Ancient Greek διαπασῶν (diapasôn), that is διά (diá, “through”) + πασῶν (pasôn, “all”) (χορδῶν (khordôn, “notes”)), “through all (notes)”.

noun

1. (music) The musical octave.
   2 to 1, which is a duple ratio, forms the [symphony] diapason 1818, Iamblichus, translated by Thomas Taylor, Life of Pythagoras, page 328
2. (by extension, literary) The range or scope of something, especially of notes in a scale, or of a particular musical instrument.
3. (music) A tonal grouping of the flue pipes of a pipe organ.
4. A harmonious outpouring of sound.
   he could hear nothing except the rattle of the crickets and the swelling diapason of the frogs […] 1961, Graham Greene, A Burnt-Out Case