Crescendo

Part of speech: noun (n.)

1. A gradual increase in the strength and fullness of tone with which a passage is performed.

2. A pssage to be performed with constantly increasing volume of tone.

Part of speech: adjective (a.)

With a constantly increasing volume of voice; with gradually increasing strength and fullness of tone; -- a direction for the performance of music, indicated by the mark, or by writing the word on the score.