In music notation, a segno is a special sign placed above the staff to mark the head of a long section that repeats. It resembles a stylized 'S' with two dots and a slash through it, and looks something like this:
_
/ /
\ /
. X .
/ \
/ _/
It is used in conjunction with the dal segno notation. When used together on the staff, they look something like this (a dollar sign ($) is the closest ASCII approximation to a proper segno):
/\ $ D.S.
---| /----------------------------|---------------------||
|/ | | ||
---/------------------------------|---|----|------------||
/| 4 | | | | * ||
-/-|/\--------------------|----|--|---|----|---*---|----||
| | | 4 | | | | | * | | ||
|--|--|--------|-----|----|----|--|--*--------|----|----||
\ | | | | | * | | | ||
--\|_/---------|-----|---*--------|-----------|---------||
| | *
\| -*--
| 
