from
The Collaborative International Dictionary of English v.0.48
Diapason \Di`a*pa"son\, n. [L., fr. Gr. diapasw^n (i. e., "h
dia` pasw^n chordw^n symfoni`a the concord of the first and
last notes, the octave); dia` through + pasw^n, gen. pl. of
pa^s all: cf. F. diapason. Cf. {Panacea}.]
1. (Gr. Mus.) The octave, or interval which includes all the
tones of the diatonic scale. Compare {disdiapason}.
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2. Concord, as of notes an octave apart; harmony.
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The fair music that all creatures made . . .
In perfect diapason. --Milton.
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3. The entire compass of tones; the entire compass of tones
of a voice or an instrument.
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Through all the compass of the notes it ran,
The diapason closing full in man. --Dryden.
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4. A standard of pitch; a tuning fork; as, the French normal
diapason.
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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.
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