Abstract: A prosthetic socket is adapted to support a prosthesis and is also adapted to be worn on a stump of a partially amputated limb. This socket has a coupler for holding the prosthesis along a prosthetic axis. The socket also has a cup with an inside surface and an outside surface. This inside surface is adapted to fit on the stump. The coupler is centrally attached to the cup to face outwardly from the outside surface. The cup contains a separated plurality of contractible cavities distributed around the prosthetic axis between the inside surface and the outside surface to provide cushioning by allowing deflection of the cup along the prosthetic axis into the cavities to contract the cavities. The cup can be formed with a plurality of angularly spaced, elongate, blind holes extending away from a central location. These blind holes can be plugged to prevent intrusion of debris. In an alternative cup, a molded cap can be affixed over a molded boot, while leaving interspaces that form spaced, closed cavities.