In dynamics music notation, a decrescendo (also called a diminuendo) is drawn as an elongated greater-than (>) symbol positioned beneath the staff or in the middle of a grand staff, although sometimes it is abbreviated as "decresc." (or "dim.") instead. It indicates that the loudness of the music should decrease gradually and smoothly from the point where the crescendo begins to where it ends. The word means "decreasing" in Italian.
Usually, a specific dynamics marking will be indicated at the end of the decrescendo to tell the musician how loud the music should be when it ends.
When drawn on the staff, crescendo looks something like this (complete with time signature, a quarter note scale, and piano and forte markings):
/\
---| /------------------------------|--------------------||
|/ | ||
---/-----------------------------|--|--------------------||
/| 4 * | | | ||
-/-|/\-----------|-----*---------|--|--|----|------------||
| | | 4 | | * | | | | | ||
|--|--|----------|----|----|----*---|--|----|----|----|--||
\ | | | | | | * | | | ||
--\|_/----------------|----|--------|------*-----|----|--||
| | * |
\| -*--
_____________
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f ___________ > p
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