caltrop

American  

[kal-truhp] / ˈkæl trəp /

Also calthrop

noun

1. any of several plants having spiny heads or fruit, as those of the genera Tribulus and Kallstroemia, or the star thistle, Centaurea calcitrapa.

2. an iron ball with four projecting spikes so disposed that when the ball is on the ground one of them always points upward: used to obstruct the passage of cavalry, armored vehicles, etc.

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caltrop British  

/ ˈkælθrəp, ˈkæltrəp /

noun

1. any tropical or subtropical plant of the zygophyllaceous genera Tribulus and Kallstroemia that have spiny burs or bracts

2. another name for water chestnut

3. another name for the star thistle

4. military a four-spiked iron ball or four joined spikes laid upon the ground as a device to lame cavalry horses, puncture tyres, etc

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Etymology

Origin of caltrop

before 1000; Middle English calketrappe, Old English calcatrippe, colte-træppe, equivalent to calce- (< Latin calci-, stem of calx spur, heel) + træppe trap ¹

Example Sentences

It released images of old desktop computer towers and crude weapons like steel caltrops and spiked metal balls, which allegedly belonged to the group.

From Seattle Times

Police said they encountered large-caliber weapons, explosives and caltrops, as well as snipers.

From Los Angeles Times

A common complaint of bots is that a loose cord or rug tassel will jam the brushes and the motor, stopping the robot like a caltrop.

From Salon

The military instrument called “caltrop” resembles that fruit, from which it may have been evolved; and the appellation tribolo is one of the etymological elements in “caltrop.”

From Project Gutenberg

In fact, they are homemade caltrops, designed to puncture the boots of infantrymen and the tires of their vehicles, and were made, by the bucketful, by welders in the same shops.

From New York Times