Wiktionary
squaresail
n. A sail bent to a horizontal yard set athwartships.
Usage examples of "squaresail".
By now the courses had been trimmed, the studdingsails (in effect long strips of canvas to be hoisted up alongside each of the squaresails to make them wider, the tops held out by the stunsail booms, which slid out to form extensions of the yards) had been brought up on deck from the sail room and the special halyards were ready.