| 1. | (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 |
| Noun | 1. | water chestnut - a plant of the genus Trapa bearing spiny four-pronged edible nutlike fruits Synonyms: water chestnut plant, caltrop |
| 2. | water chestnut - Chinese sedge yielding edible bulb-shaped tubers Synonyms: Chinese water chestnut, Eleocharis dulcis | |
| 3. | water chestnut - edible bulbous tuber of a Chinese marsh plant |