\begin{definition}[Definition:Interior Point (Topology)/Definition 1]
Let $T = \struct {S, \tau}$ be a topological space.
Let $H \subseteq S$.
Let $h \in H$.
Then $h$ is an '''interior point''' of $H$ {{iff}}:
:$h \in H^\circ$
where $H^\circ$ denotes the interior of $H$.
\end{definition}