The term describes a style of musical expression characterized by distinct, abrupt shifts in volume. Rather than smooth, gradual crescendos and diminuendos, the music moves between clearly defined loud and soft sections. Think of it as a musical staircase, where each step represents a specific dynamic level, and the music proceeds from one step to another without a ramp in between. A practical illustration would be a piece transitioning directly from forte (loud) to piano (soft) with no intervening mezzo forte or mezzo piano.
This approach to musical expression was particularly prominent in the Baroque era. Its effectiveness lies in its ability to create stark contrasts and clear articulation of musical phrases. Composers employed this technique to delineate sections within a piece, highlight thematic material, and add dramatic impact. Furthermore, the relative limitations of keyboard instruments of the time, such as the harpsichord (which lacked the ability to create gradual dynamic changes), contributed to the prevalence and stylistic suitability of this method.
