Main Entry: water chestnut

Function: noun

Date: 1847

1 : any of a genus (Trapa, especially T. natans of the family Trapaceae, the water-chestnut family) of Old World aquatic herbs sometimes grown as ornamentals; also : its edible nutlike spiny fruit
2 : a whitish crunchy vegetable used especially in Chinese cooking that is the peeled and often sliced tuber of a sedge (Eleocharis dulcis syn. E. tuberosa) native to Asia but widely cultivated elsewhere; also : the tuber or the sedge itself