Diminuendo (or decrescendo) is marked with a reversed “hairpin” ( > ) or the word dim. It is the art of fading with subtlety, without losing expressiveness or tension.
The finest examples are the endings of Chopin's nocturnes, which dissolve into silence like morning mist. In symphonic music, diminuendo often prepares the listener for the return of a main theme — like a quiet breath before the next.
Diminuendo is the mirror image of crescendo, and together they form the “dynamic wave” that underlies expressive phrasing. A particularly subtle device is morendo (“dying away”) — when diminuendo is combined with a barely perceptible slowing, and the music seems to dissolve into silence. Mastering the fade of a sound to the very edge of audibility is a mark of a mature performer.
