The octave, or interval which includes all the tones of the diatonic scale. Compare disdiapason.

Concord, as of notes an octave apart; harmony.

The entire compass of tones; the entire compass of tones of a voice or an instrument.

A standard of pitch; a tuning fork; as, the French normal diapason.

The entire register or range of sound of an instrument or voice from the highest to lowest pitch.

The word diapason (pronounced ) is another name for the musical interval of the octave, especially in the context of Pythagorean intervals. In other contexts, it can mean the range of a musical instrument or voice.