The multiplication sign $\times$ is used in many places in mathematics other than arithmetic (in set theory – denoting the Cartesian product of two sets, to name an example).
The division sign $\div$, on the other hand, is seemingly only used in arithmetic. Wikipedia's list of mathematical symbols lists the sign together with $/\!$, but only provides only one example for $\div$, i.e. its use in arithmetic.
Where else in mathematics is the division sign $\div$ (the obelus) used? Googling is of no help.