Square rig is a nautical term that describes the type of sail set on a sailing vessel. If you're talking with fellow seafaring enthusiasts or are trying to impress your friends and family with your knowledge of boating lingo, there are a number of synonyms you can use in place of square rig. These include square-set rig, square sails, square-rigged sails, or simply squares. Each of these terms refers to the same type of sail configuration, which features a large, rectangular-shaped sail that is rigged to a mast and yardarm. Using these synonyms will help you communicate more effectively with other sailors and will enhance your understanding of the technical aspects of sailing.