The term 'Pogo Stick Part' is referring to a SPRING, which is a device used in pogo sticks to provide the necessary bounce. A SPRING is a mechanical device that stores energy and can be made from a variety of materials such as metal or rubber. It is typically used to absorb shock and return to its original shape after being compressed or stretched. Springs are an essential part of pogo sticks, as they provide the necessary bounce for the user to jump.