In music, a scale is a set of notes in order of their pitch (that is, their frequency).[1] If the scale starts with the note which has the lowest pitch and goes up to the note with the highest pitch, the scale is called ascending.[2] If the scale starts with the note which has the highest pitch and goes down to the note with the lowest pitch, the scale is called descending.[3] Scales are often the same both ascending and descending, but this is not always true. Very often, a scale is defined over an interval (such as an octave). The most common scales use intervals of five, six or seven different notes.