The sabre or saber (see spelling differences) is a type of backsword, usually with a curved, single-edged blade and a rather large hand guard, covering the knuckles of the hand as well as the thumb and forefinger.

Ultimately based on a medieval type of single-edged weapon, the sabre was adopted as the weapon of heavy cavalry in Early Modern warfare. Although sabres are typically thought of as curved-bladed slashing weapons, those used by the heavy cavalry of the 17th to 19th centuries often had straight and even double-edged blades more suitable for thrusting. The length of sabres varied, and most were carried in a scabbard hanging from a shoulder belt known as a baldric or from a waist-mounted sword belt, usually with slings of differing lengths to permit the scabbard to hang below the rider's waist level.