A series of notes into which the octave is divided according to specific systems. These systems or modes are used as the basis for composing music. The major and minor scales are modes, as well as the gypsy scale, the Gregorian modes, rhythmic modes, etc. ("church modes" or "ecclesiastical modes") a system of classifying pieces based on the organization of pitches. In the middle Ages, mode was defined through a combination of range and final. If melodies were above the final, they were authentic, if they ranged both above and below the final, they were plagal. Mode also had melodic implications--each mode had characteristic intervals and musical gestures. An introduction to church modes is available.