CALTRAPS
Noun
caltraps
plural of caltrap
Source: Wiktionary
CALTRAP
Cal"trop, Cal"trap, n. Etym: [OE. calketrappe, calletrappe, caltor
(in both senses), fr. AS. collræppe, calcetreppe, sort of thistle;
cf. F. chaussetrape star thistle, trap, It. calcatreppo,
calcatreppolo, star thistle. Perh. from L. calx heel + the same word
as E. trap. See 1st Trap.]
1. (Bot.)
Definition: A genus of herbaceous plants (Tribulus) of the order
Zygophylleæ, having a hard several-celled fruit, armed with stout
spines, and resembling the military instrument of the same name. The
species grow in warm countries, and are often very annoying to
cattle.
2. (Mil.)
Definition: An instrument with four iron points, so disposed that, any
three of them being on the ground, the other projects upward. They
are scattered on the ground where an enemy's cavalry are to pass, to
impede their progress by endangering the horses' feet.
Source: Webster’s Unabridged Dictionary 1913 Edition