Definition: A genus of herbaceous plants (Tribulus) of the order
Zygophylleae, 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.
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.
