The center part of a wheel or circle is called the hub.
The hub is the core component that connects to the axle, allowing the wheel to rotate. In a circle, the center point is often referred to simply as the center, which is equidistant from all points on the circumference. Understanding the hub is crucial for mechanics, as it plays a vital role in the functionality and stability of the wheel, whether it’s on a bicycle, a car, or any circular object.