a series of chords that follows principles and guidelines defined by the overtone series and tradions of the common practice period, generally within a tonal framework. This also is refered to as harmonic function. In the tonal systm, progressions occur when root movements are the following general intervals: Up by Second Down by Third Up by Fourth (or down by fifth) except V and vii°, which do not resolve to iii (or III in minor) See also the section on Basic Harmonic Function for more details.