noun

1. a ship with large tanks in the hull for carrying a cargo of oil or other liquids
2. ☆
   1. tank car
   2. a truck, semitrailer, or trailer with a tank for transporting liquids, as gasoline, or dry commodities in bulk
3. ☆ an aircraft designed to carry liquids, as chemicals, fuels, etc., for dumping on fires, refueling other aircraft in flight, etc.