What is an aheadset?

What is an aheadset? 2 bearings and storage shells that combine fork and frame. The fork is freely movable so that you can steer.

Aheadset:
2 bearings and storage shells that combine fork and frame. The fork is freely movable so that you can steer.

Relevant contributions:
Spring check bike

Relevant products: 
Upper pipe bag for the cell phone