Definition of caltrop
1a
caltrops also calthrops plural in form but singular or plural in construction
: star thistle sense 1
b
: puncture vine
also
: any of various related herbs (genera Tribulus and Kallstroemia) of the same family (Zygophyllaceae, the caltrop family)
2
: a device with four metal points so arranged that when any three are on the ground the fourth projects upward as a hazard to the hooves of horses or to pneumatic tires
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Merriam-Webster unabridged
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Time Traveler for caltrop
The first known use of caltrop was in the 15th century
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