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 (kăl′trəp, kôl′-)
2. Any of various plants bearing small spiny fruits, especially of the genera Tribulus and Kallstroemia.
3. A metal device with four projecting spikes so arranged that when three of the spikes are on the ground, the fourth points upward, used as a hazard to pneumatic tires or to the hooves of horses.

[Middle English calketrappe, from Norman French and from Old English calcatrippe, thistle, both from Medieval Latin calcatrippa, thistle : possibly from Latin calcāre, to tread on; see calque + trappa, trap (of Germanic origin).]


(ˈkæltrəp) or




1. (Plants) any tropical or subtropical plant of the zygophyllaceous genera Tribulus and Kallstroemia that have spiny burs or bracts
2. (Plants) water caltrop another name for water chestnut1
3. (Plants) another name for the star thistle
4. (Military) military a four-spiked iron ball or four joined spikes laid upon the ground as a device to lame cavalry horses, puncture tyres, etc
[Old English calcatrippe (the plant), from Medieval Latin calcatrippa, probably from Latin calx heel + trippa trap1]


or cal•trap

(ˈkæl trəp)

also cal•throp


1. any of several plants having spiny heads or fruit, as those of the genera Tribulus and Kallstroemeria.
2. an iron ball with four projecting spikes, one of which always points upward when the ball is placed on the ground: used to obstruct cavalry, vehicles, etc.
[before 1000; Middle English calketrappe, Old English calcatrippe]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.caltrop - tropical annual procumbent poisonous subshrub having fruit that splits into five spiny nutletscaltrop - tropical annual procumbent poisonous subshrub having fruit that splits into five spiny nutlets; serious pasture weed
genus Tribulus, Tribulus - annual or perennial herbs or subshrubs of warm regions
subshrub, suffrutex - low-growing woody shrub or perennial with woody base
2.caltrop - a plant of the genus Trapa bearing spiny four-pronged edible nutlike fruitscaltrop - a plant of the genus Trapa bearing spiny four-pronged edible nutlike fruits
genus Trapa, Trapa - small genus of Eurasian aquatic perennial herbs: water chestnut
Jesuits' nut, Trapa natans, water caltrop - a variety of water chestnut
ling, ling ko, Trapa bicornis - water chestnut whose spiny fruit has two rather than 4 prongs
aquatic plant, hydrophyte, hydrophytic plant, water plant - a plant that grows partly or wholly in water whether rooted in the mud, as a lotus, or floating without anchorage, as the water hyacinth
3.caltrop - Mediterranean annual or biennial herb having pinkish to purple flowers surrounded by spine-tipped scales; naturalized in America
centaury - any plant of the genus Centaurea
References in periodicals archive ?
Chris Shanks landed one of 7lb on fly while Joe Clark also landed a very fresh run sea liced 8lb salmon further upriver at the Jack Rock caught on a Black and Orange fly.
The fish, which weighed approximately 9lb, was brought to the net at the Jack Rock.
The court noted that this was not an isolated incident and that it had been apprised of in excess of 400 separate incident reports, 125 of which involved placement of jack rocks (a jack rock is a metal device consisting of two large nails, twisted and welded together which, when thrown into the street, punctures a vehicle's tires).
Rob Stephenson from Seaton Delaval landed the 9lb springer at the Jack Rock above the Tidal Beat last Friday.
The fulmar petrel also breeds along the cliffs and numbers more than 200 pairs, and a substantial number of the UK's cormorants have bred on Marsden Rock and Jack Rock in recent years.
This may have brought in some spring fish with the tidal at Warkworth and areas such as Morwick, Jack Rock and Black Doors worth a go.
The 11lb sea-liced fish was taken on an Orange Conrad at the Jack Rock near Warkworth.
The fish weighed 8lb and was caught and carefully returned at the Jack Rock.
As well as Marsden Rock, the haunt of nesting cormorants, there are pillars called Lot's Wife, Jack Rock and Pompey's Wife.
20am ( as Darren Thomas Ewart from Ashington landed a cracking sea-liced 11lb salmon at the Jack Rock near Morwick, on an Orange Conrad lure.