A shaft is a long, cylindrical component used to transmit power or motion in machinery. It often connects rotating parts, such as gears or wheels, allowing them to work together efficiently. Shafts can be made from various materials, including metal and composite materials, depending on their application and required strength. In engineering, shafts are crucial in devices like electric motors, pumps, and automobiles. They can be solid or hollow and may have different diameters and lengths based on their specific use. Proper design and maintenance of shafts are essential for the reliability and performance of the machinery they support.