Racer /(rā"sẽr)/

Ra·cer

Racer

n.
  1. One who, or that which, races, or contends in a race; esp., a race horse.
    And bade the nimblest racer seize the prize.
  2. The common American black snake. (Zool.)
  3. One of the circular iron or steel rails on which the chassis of a heavy gun is turned. (Mil.)