A full-rigged ship or fully rigged ship is a sailing vessel's sail plan 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. Such vessels also have each mast stepped in three segments: lower mast, top mast, and topgallant mast. Other large, multi-masted sailing vessels may be regarded as ships while lacking one of the elements of a full-rigged ship, e.g. having one or more masts support only a fore-and-aft sail or having a mast that only has two segments.