I was reading about the axiom of regularity on Wikipedia.
It is stated that:
In mathematics, the axiom of regularity (also known as the axiom of foundation) is an axiom of Zermelo–Fraenkel set theory that states that every non-empty set $A$ contains an element that is disjoint from $A$.
$$\forall x\left(x\neq \emptyset\implies\exists y\in x\left(y\cap x=\emptyset\right)\right)$$
How can this be correct?
If $A$ contains an element $x$, then $x$ can not be disjoint from $A$, because $x$ belongs both to $A$ and to the set containing only $x$.
What am I misunderstanding?