Water chestnut \Wa"ter chest"nut\ (Bot.) The fruit of {Trapa natans} and {Trapa bicornis}, Old World water plants bearing edible nutlike fruits armed with several hard and sharp points; also, the plant itself; -- called also {water caltrop}. Saligot \Sal"i*got\, n. [F.] (Bot.) The water chestnut ({Trapa natans}).
Trapa natans n : a variety of water chestnut [syn: {water caltrop}, {Jesuits' nut}]