"Deminuedo" is a musical term that refers to a gradual decrease in loudness or volume, similar to the term "decrescendo." It instructs musicians to play softer over a specified passage, creating a sense of fading or subtlety in the music. This technique can enhance emotional expression and dynamic contrast within a piece.
The term is Italian and spelled diminuendo. The Spanish term is disminuyendo.It means "decreasing" as in becoming softer, synonymous with decrescendo.
A cresendo is when start soft and work your way up. Actually, that's not exactly correct. Crescendo simply means to gradually get louder. You don't necessarily start soft, you get louder from whatever volume level you are currently playing.