Definition of accrescendo:
(n) :
(figuratively) A gradual increase of anything, especially to a dramatic climax.
(adv) :
(music) Gradually increasing in force or loudness.
(n) :
(music) An instruction to play gradually more loudly, denoted by a long, narrow angle with its apex on the left ( < ), by musicians called a hairpin.
(v) :
To increase in intensity; to reach or head for a crescendo.
(n) :
(figuratively, nonstandard) The climax of a gradual increase.