What "camming device" means in rock climbing

A camming device, also known as a cam, is a type of rock climbing equipment used to protect a climber from a fall. It typically consists of three or four cam lobes that expand and contract as the device is placed into a crack or crevice in the rock. The camming action of the device provides a secure anchor point for the climber's rope, allowing them to continue climbing with reduced risk of injury.