What is "cheval de frise"

1680s, from French, literally "horse of Frisia," supposedly because it was first employed there as a defense against cavalry; from French cheval "horse" (see cavalier (n.)). Plural chevaux de frise.

n. 1 (context military English) An obstacle made of wood with spikes, for use against attacking cavalry. 2 Protective row of spikes or broken glass set into the top of a wall and used to prevent intrusion. 3 (context archaic fashion English) The jagged edge of 18th-century women's clothing.

The cheval de frise (plural: chevaux de frise , " Frisian horses") was a medieval defensive anti-cavalry measure consisting of a portable frame (sometimes just a simple log) covered with many projecting long iron or wooden spikes or spears. They were principally intended as an anti- cavalry obstacle but could also be moved quickly to help block a breach in another barrier. They remained in occasional use until they were replaced by wire obstacles just after the American Civil War. During the Civil War, the Confederates used this type of barrier more often than the Union forces. During World War I, armies used chevaux de frise to temporarily plug gaps in barbed wire. Chevaux de frise of barbed wire were used in jungle fighting on south Pacific islands during World War II.

The term is also applied to defensive works comprising a series of closely set upright stones found outside the ramparts of Iron Age hillforts in northern Europe.