An interval of eight pitch names; twelve half steps.

Eight full tones above the key note where the scale begins and ends.

(Latin: 'octavus', 'eigth'). The interval of an eight, eg: from the notes C to C or D to D.

The interval between two musical notes, the upper one of which has twice the pitch of the lower one. In a major or minor scale, the distance of this interval lies eight steps* away, hence the term “octave.” (*in the major or minor scales, the eight steps are actually a combination of “whole steps” and “half-steps”)