A buttress, or second wall, added to strengthen another.
Related term(s): None
Source information: Britton, John, F.S.A. A Dictionary of the Architecture and Archaeology of the Middle Ages. J. Le Keux, illus. London: Longman, Orme, Brown, Green, and Longmans, Paternoster Row; and the Author, Burton Street, 1838. 2.