An octave is a musical interval that spans eight notes in a scale. In Western music, it is commonly represented by the distance between one note and another note with the same name, such as from C to the next C. The frequency of the higher note is typically double that of the lower note, creating a harmonious sound. In addition to music, the term "octave" is also used in other fields, such as mathematics and acoustics. In mathematics, an octave can refer to a logarithmic scale that measures frequency, while in acoustics, it describes the range of sound frequencies that are perceived as similar.