caltrop
/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...
- The plot progresses like a horse marching over caltrops, jerking wildly every time its foot encounters the next point.
- It was a combination of towers, palisades, ditches, abatis, and caltrops to slow the attacking Gauls, so that Roman missile engines could more effectively engage them.
- He didn't know what weapon he possessed, if any, beyond the caltrops.
2A creeping plant with woody carpels that typically have hard spines and resemble military caltrops.
- Genus Tribulus, family Zygophyllaceae.
- Caltrop is a perennial herb that can infest a wide variety of crops and pastures.
- Caltrop is an herbaceous annual that commonly grows prostrated on the ground.
3 (also water caltrop) another term for water chestnut (sense 3).
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. sense 1 was probably adopted from French.