1. To grow in loudness or intensity.
2. Etymology: crescendo is an Italian word which comes from the Latin word crescere, "to grow" or "to increase".

In music, it refers to an increase in loudness, and also to the point at which the sound is at maximum volume.

It may also be used to refer to things other than sound, but it always indicates that there is a increase in the volume of something or that a person is at the peak of an increase of some kind.