DIAPASONS
Noun
diapasons
plural of diapason
Source: Wiktionary
DIAPASON
Di`a*pa"son, n. Etym: [L., fr. Gr. i. e., diapason. Cf. Panacea.]
1. (Gr. Mus.)
Definition: The octave, or interval which includes all the tones of the
diatonic scale.
2. Concord, as of notes an octave apart; harmony.
The fair music that all creatures made . . . In perfect diapason.
Milton.
3. The entire compass of tones.
Through all the compass of the notes it ran, The diapason closing
full in man. Dryden.
4. A standard of pitch; a tuning fork; as, the French normal
diapason.
5. One of certain stops in the organ, so called because they extend
through the scale of the instrument. They are of several kinds, as
open diapason, stopped diapason, double diapason, and the like.
Source: Webster’s Unabridged Dictionary 1913 Edition