ˈtrāpə, -rapə noun
Usage: capitalized
Etymology: New Latin, probably short for (assumed) Medieval Latin calcitrappa caltrop — more at caltrop
: a small Old World genus of aquatic herbaceous plants with finely dissected submerged leaves, rhombic floating leaves that have inflated spongy petioles, and solitary white flowers followed by horned or spiny fruits — see trapaceae , water chestnut