Square rig
Square rig is a generic type of sail and rigging arrangement in which a sailing vessel's primary driving sails are carried on horizontal spars that are perpendicular to the median plane of the keel and masts of the vessel. These spars are called and their tips, outside the lifts, are called the. A ship mainly rigged so is called a square-rigger.
In "Jackspeak", it also refers to the dress uniform of junior ratings.