caltrop
/ˈkæltrəp/(亦作caltrap)
noun
1
- a spiked metal ball thrown on the ground to impede wheeled vehicles or (formerly) cavalry horses（阻止有轮车辆或旧时为阻止骑兵而用的）铁蒺藜。
2
- a creeping plant with woody carpels that typically have hard spines and resemble military caltrops矢车菊; 蒺藜; 欧菱。
2.1
- Genus Tribulus, family Zygophyllaceae.蒺藜属, 蒺藜科。
3
- （亦作water caltrop）another term for WATER CHESTNUT (in sense 3).同WATER CHESTNUT （义项3）.
词源
Old English calcatrippe, denoting any plant which tended to catch the feet, from medieval Latin calcatrippa, from calx 'heel' or calcare 'to tread' + a word related to TRAP1 . Sense 1 was probably adopted from French.