1. Tropical annual procumbent poisonous subshrub having fruit that splits into five spiny nutlets; serious pasture weed
   "Farmers struggle to control caltrop in their pastures";
   - devil's weed, Tribulus terrestris
    
2. A plant of the genus Trapa bearing spiny four-pronged edible nutlike fruits
   "The caltrop plant's unique fruits floated on the surface of the pond";
   - water chestnut, water chestnut plant
    
3. Mediterranean annual or biennial herb having pinkish to purple flowers surrounded by spine-tipped scales; naturalized in America
   "caltrop is considered an invasive weed in many parts of the United States";
   - star-thistle, Centaurea calcitrapa

Derived forms: caltrops

Type of: aquatic plant, centaury, hydrophyte, hydrophytic plant, subshrub, suffrutex, water plant

Part of: genus Trapa, genus Tribulus, Trapa, Tribulus

Encyclopedia: Caltrop