tribolus

trĭbŭlus ( trĭbŏl- ), i, m., = tribolos, an instrument resting on three of its iron prongs, while a fourth projected upward, thrown on the ground to impede an enemy's cavalry, a caltrop.

I.

Lit.:

tribulos abjecerunt,

Veg. Mil. 3, 24.—

II.

Transf., from its resemblance in form.

A.

A kind of thorn or thistle, land-caltrops: Tribulus terrestris, Linn.; Verg. G. 1, 153; Ov. M. 13, 803; Plin. 21, 15, 54, § 91:

spinae et tribuli,

Vulg. Gen. 3, 18.—

B.

A kind of water-plant bearing a prickly nut of a triangular form, water - chestnut, water - caltrops: Trapa natans, Linn.; Plin. 21, 16, 58, § 98.