- caltrop⇄caltrop orcaltrap, noun.
Now often caltrops.
1. any one of various plants having pointed, spiny flower heads or fruit;
a. star thistle.
b. any plant of various herbs of South Europe having spiny seeds.
c. water chestnut o - caltrop⇄water chestnut orcaltrop
1. any one of a genus of aquatic plants of the evening-primrose family, whose nutlike fruit contains a single, large, edible seed, especially a species native to Eurasia that has become a troublesome weed in parts of the Uni