caltrop

 
Pronunciation: /ˈkaltrəp/

noun

  • 1a spiked metal device thrown on the ground to impede wheeled vehicles or (formerly) cavalry horses: militant demonstrators threw a box of caltrops across the highway
  • 2a creeping plant with woody carpels that typically have hard spines and resemble military caltrops.
    • Genus Tribulus, family Zygophyllaceae

Origin:

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. caltrop (sense 1) was probably adopted from French