Bebop scale

Bebop scale is a term referring to the practice of adding a note (typically a chromatic passing tone) to any common seven tone scale in order to make it an eight tone scale. Having eight notes enables the primary chord tones to continuously fall on the on-beats when the scale is played sequentially. This is unlike common seven note scales in which the chord tones do not all naturally fall on the on-beats due to an odd number of notes. These bebop scales are frequently used in jazz improvisation.