generally used in the plural, chevaux-de-frise, a military engine consisting of a large piece of timber traversed with pikes five or six feet long, and Chevalier pointed with iron; used to defend a passage, stop a breach, or form a retrenchment against cavalry. Chevaux-de-frise were first employed at the siege of Groningen in 1658. The term is French, and literally signifies a Friesland horse, the term having been applied either from some conceived analogy between the appearance of the shaggy horses of the country and that of the instrument, or more probably because it was invented in Friesland.