A machine that requires only the force of a human to perform work The six types are: the lever, the wheel and axle (including the gear), the pulley, the inclined plane, the wedge, and the screw
any of various elementary mechanisms formerly considered as the elements of which all machines are composed and including the lever, the wheel and axle, the pulley, the inclined plane, the wedge, and the screw
any of various elementary devices considered as the elements of which all machines are composed and including the lever, the wheel and axle, the pulley, the inclined plane, the wedge, and the screw