noun

• One who paces.
• In harness racing, a horse with a gait in which the front and back legs on one side take a step together alternating with the legs on the other side; as opposed to a trotter.
• A pacemaker (one who sets the pace in a race).
• (Australia) A mechanical pencil.
• (rail transport) A British lightweight railbus diesel multiple unit of class 140, 141, 142, 143 or 144.