Decrescendo (noun)

1. A gradual decrease in volume or intensity of sound in music.
2. A gradual tapering off or decrease in any activity or process.

Origin:

From italian decrescendo, from decrescere ('to decrease, diminish'), from latin decrescere, from de- ('down, away') + crescere ('to grow').

Examples:

1. The symphony ended with a beautiful decrescendo, leaving the audience in awe.
2. The rainfall started with a heavy downpour, then decrescendo-ed to a light drizzle.
3. The company's profits showed a decrescendo after the first quarter of the year.