There are numerous points inside every circle but a particular point is exactly middle to the circle.
The middle point of the circle maintains same distance from every point on the circumference of the circle. So, the point is known as centre of the circle.
The centre of a circle is a point geometrically. So, it is also represented same as the notation of the point.
Point $C$ is an inside point of the circle and it maintains equal distance from every point on the circumference of the same circle.
Therefore, the point $C$ is called as centre of the circle.