sloop, fore-and-aft-rigged, single-masted sailing vessel with a single headsail jib. A sloop differs from a cutter in that it has a jibstay—a support leading from the bow to the masthead on which the jib is set. A sloop of war was a small warship, variously rigged as a barque, brig, brigantine, or ship, that carried fewer than 18 guns in the British navy and fewer than 24 in the American navy. These vessels played an active role in the American Revolution and the French Revolutionary Wars. The sloop disappeared as a warship in the mid-19th cent., but during World War II the British revived the term to designate a small escort vessel armed with 4-in. (10.2-cm) guns and depth charges.