Hist. A spiked barrier fixed in or across a road or passage, as a defence against sudden attack, esp. of men on horseback.

Military. An iron ball armed with four sharp prongs or spikes, placed like the angles of a tetrahedron, so that when thrown on the ground it has…

transferred. A similar contrivance used for other purposes: see quots., and cf. hearse, n.

= caltrop, n. 2.

A pike or stake with a spike or sharp point at the head, used to provide a defence against cavalry by being fixed in the ground at an angle…

a pike or stake with a spike or sharp point at the head, used to provide a defence against cavalry by being fixed in the ground at an angle alongside…

Military. A caltrop; = crow's foot, n. 3.

A defensive appliance of war, employed chiefly to check cavalry charges, and stop breaches: see description in the quotations.

= cheval de frise, n.

A harrow used for a cheval-de-frise, and laid in the way or in breaches with the points upward to obstruct enemy. Obsolete.

Military. A caltrop; = crowfoot, n. 6.

In field fortification, a conical pit with a pointed stake fixed vertically in the centre, rows of which are dug before a work to hinder an enemy's…

= caltrop, n. 2.

= cheval de frise, n. 1. Also transferred.

Military. One of the transverse spikes or poles of a cheval-de-frise.

In South-East Asia: a sharpened (frequently poisoned) bamboo stake set in the ground as a defence, or at the bottom of a camouflaged hole to form a…

(apparently) an obstacle intended to impede the movement of cavalry (see quot. 1863).