The compass needle always points to the center of the circle.

The middle point of a circle or sphere, equidistant from all points on its boundary.
Find the center of the square.
The bullseye is the center.
The dot marks the center.
dead center
center of the universe
center of attention
middle
midpoint
heart
The bullseye is the center of the target.

The point or part that is equally distant from all sides of something.
Find the center of the circle.
The store is at the town center.
He stood in the center of the room.
center of attention
center of the universe
center of gravity
middle
heart
core