A full-rigged ship or fully rigged ship is a sailing vessel with three or more masts, all of them square-rigged. A full-rigged ship is said to have a ship rig or be ship-rigged. Sometimes such a vessel will merely be called a ship in 18th- to early-19th-century and earlier usage, to distinguish it from other vessels such as schooners, barques, barquentines, brigs, etc. Alternatively, a full-rigged ship may be referred to by its function instead, as in collier or frigate, rather than being called a ship. In many languages the word frigate or frigate rig refers to a full-rigged ship.