The term indicates a directive to gradually decrease the tempo of a musical piece, and the inclusion of molto signifies a considerable slowing down. It instructs the performer to execute a more pronounced deceleration than a simple instruction to slow the tempo would imply. For instance, a passage marked with this instruction would necessitate a clearly perceptible reduction in speed, affecting the overall feel and impact of the music.
This instruction contributes significantly to the expressive capabilities of music, enabling composers to shape the emotional landscape of their compositions. Its application can heighten drama, create a sense of resolution, or evoke feelings of reflection and introspection. Throughout musical history, composers have utilized this technique to add depth and nuance to their work, shaping the listeners experience.