Definition:Symmetric Difference/Definition 2

Definition
The symmetric difference between two sets $S$ and $T$ is written $S \symdif T$ and is defined as:
 * $S \symdif T = \paren {S \cup T} \setminus \paren {S \cap T}$

where:
 * $\setminus$ denotes set difference
 * $\cup$ denotes set union
 * $\cap$ denotes set intersection.

That is, $S \symdif T$ is the set of elements that are in either $S$ or $T$, but not both.

Also see

 * Equivalence of Definitions of Symmetric Difference