Definition:Interior of Circle

Definition

Let $\CC$ be a circle embedded in the plane whose radius is $r$ and whose center is at $O$.

The interior of $\CC$ is the set of points in the plane whose distance from $O$ is (strictly) less than $r$.

Also see

• Definition:Exterior of Circle

Sources

• 1933: D.M.Y. Sommerville: Analytical Conics (3rd ed.) ... (previous) ... (next): Chapter $\text {III}$. The Circle: $10$.