Gear
A round or cylindrical mechanical component with teeth used to transmit power. Gears are designed to intersect with one another and can alter the speed, torque, or direction of mechanical energy.
See also Bevel Gear; Bull Gear; Conical Gear; Double-Helical Gear; Drive Gear; Driven Gear; Helical Gear; Herringbone Gear; Idler Gear; Internal Gear; Left-Hand Helical Gear; Miter Gear; Pinion Gear; Spur Gear; Switch Gear; Worm Gear.