An interval spanning seven diatonic degrees, eleven semitones. An octave above C would be C. The frequency of a note one octave above another will have exactly twice as many Hertz as the frequency of the note an octave below it. In the example below, Middle C (the lower note) is 261.63 hertz and the C shown an octave higher is 523.25 hertz.
- The day that is one week after a feast day in the Latin Rite of the Catholic Church.
- (fencing) The eighth defensive position, with the sword hand held at waist height, and the tip of the sword out straight at knee level.