a. & adv. [ It., from crescere to increase. See Crescent. ] (Mus.) 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. [ 1913 Webster ]

n. (Mus.) (a) A gradual increase in the strength and fullness of tone with which a passage is performed. (b) A passage to be performed with constantly increasing volume of tone. [ 1913 Webster ]

‖a. & adv. [ It. ] (Mus.) With decreasing volume of sound; -- a direction to performers, either written upon the staff (abbreviated Dec., or Decresc.), or indicated by the sign. [ 1913 Webster ]