Definition:Separated

Definition
Let $X$ be a topological space.

Let $A, B \subseteq X$ such that: where $\operatorname{cl} \left({A}\right)$ denotes the closure of $A$ in $X$.
 * $\operatorname{cl} \left({A}\right) \cap B = A \cap \operatorname{cl} \left({B}\right) = \varnothing$

Then $A$ and $B$ are described as separated.