(music) An interval whose frequency ratio is not 2:1 (that of the octave), but is perceived or treated as equivalent to this ratio, and whose pitches are considered equivalent to each other as with octave equivalency.

(music) a symbol showing that the pitch of a note is to be raised by one or two octaves.

plural of octave clef

(music) A musical interval of the Western twelve-semitone system consisting of eleven semitones and spanning eight degrees of the diatonic scale. It is one semitone narrower than a perfect octave and enharmonically equivalent to a major seventh.

plural of diminished octave

(music) A musical interval of the Western twelve-semitone system consisting of twelve semitones and spanning eight degrees of the diatonic scale. It is enharmonically equivalent to an augmented seventh and is commonly referred to as an octave.

plural of augmented octave

(music) A musical interval of the Western twelve-semitone system consisting of thirteen semitones and spanning eight degrees of the diatonic scale. It is one semitone wider than a perfect octave and enharmonically equivalent to a minor ninth/compound minor second.

plural of contra-octave

plural of perfect octave