A diminuendo is a gradual decrease in loudness. The score marks it with a hairpin closing to the right or with the word diminuendo or decrescendo. Players reduce air, bow pressure, or mallet force over the indicated span so the sound fades smoothly.

Diminuendos create a sense of relaxation, distance, or closure. A long diminuendo can dissolve a phrase into silence; a short one can soften an accent or prepare a new dynamic level. The effect depends on careful control so the tone remains centered even as the volume drops.

Ensembles must taper together. If one section remains louder than the others, the balance collapses. Composers place diminuendos at structural points or to shape expressive lines. Performers often linger slightly on the final soft notes to heighten the sense of arrival.

Mastering the diminuendo is as important as mastering the crescendo for dynamic contrast.