in music, a musical interval, by which most authors, who have wrote upon the theory of music, use to express the octave of the Greeks. See Octave.

among the musical instrument makers, a kind of rule or scale, whereby they adjust the pipes of their organs, and cut the holes in their flutes, hautboys, &c., in due proportion, for performing the tones, semitones, and concords just.

DIAPASON DIAXIS, in music, a kind of compound concord, whereof there are two sorts; the greater, which is in the proportion of $10:3$; and the lesser, in that of $16:5$.