Definition:Exterior Point (Complex Analysis)/Definition 2

Definition
Let $S \subseteq \C$ be a subset of the complex plane.

Let $z_0 \in \C$.

$z_0$ is an exterior point of $S$ :
 * $z_0$ is not an interior point of $S$

and:
 * $z_0$ is not a boundary point of $S$.

Also see

 * Equivalence of Definitions of Exterior Point (Complex Analysis)