A Dictionary of Music and Musicians/Decrescendo

DECRESCENDO, decreasing—the opposite of crescendo—consists in gradually lessening the tone from loud to soft. It is also expressed by dec., decresc., and by the sign . Whether there was originally any difference between decrescendo and diminuendo or not, at present the two terms appear to be convertible. There is a splendid instance of the thing, where both words are used, at the end of the first section of the Finale of Schubert's Symphony in C, No. 9, in a decrescendo of 48 bars from fff, the bass at the same time going down and down to the low G.