The cheval de frise (plural: chevaux de frise) was a Mediaeval defensive obstacle consisting of a portable frame (sometimes just a simple log) covered with many long iron or wooden spikes or even actual 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.

The term also came to be used for any spikey obstacle, such as broken glass embedded in mortar on the top of a wall.

Etymology: Cheval de frise is French for "Frisian horse". The Frisians, having little cavalry of their own, relied heavily on such anti-cavalry obstacles.

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