A pulley is a basic device or machine made of a wheel with a rim that a cord or rope fits around. The wheel and axle of a pulley make it easier to lift heavy objects with the rope.
Ships and sailboats use pulleys — though they're often called drums — to make raising the sails less difficult. Flagpoles also have pulleys for raising and lowering the flag, many garage doors work by a pulley system, and loading docks and constructions sites use pulleys for lifting heavy things. Pulley comes from the Old French polie, with a Greek root of polidion, or "little pivot."