A binary operator representing an empty or null set, commonly used in set theory and logic.
Examples
Empty set notation (alternative to \emptyset)
A \cap B = \oslash \text{ means the sets are disjoint}
Zero element in a ring or group
R/\oslash \text{ denotes the quotient by the zero element}
Null or forbidden operation
f(x) = \oslash \text{ for } x \notin \text{dom}(f)