In music notation, a fetura is a pair of slanted lines through the topmost line of a staff. It may follow a fermata and indicates that the note should come to an abrupt and (in the case of a band or orchestra) unified stop.
On the staff, it looks something like this:
_
/\ /.\ //
---| /------------------------------------//---------------
|/ //
---/---------------------------O--------------------------
/| |
-/-|/\------------------------|----------------------------
| | | |
|--|--|-----------------------|----------------------------
\ | |
--\|_/-----------------------------------------------------
|
\|