device for transporting personnel and equipment, usually military, that can operate as a wheeled or tracked vehicle on land and as a boat in water. Two principal types appeared during World War II: the LVT (“landing vehicle, tracked”), a tractor developed for the U.S. Marine Corps, and the “duck” ( DUKW), an army-sponsored vehicle. The LVT resembled a tank, whereas the duck moved on rubber tires ashore and was propeller-driven when afloat. An air-cushion machine, such as the British Hovercraft, is not considered an amphibious vehicle.