• A pilaster, pier, or body of masonry projecting beyond the main face of the wall and intended to strengthen the wall at particular points
Catholic Encyclopedia. Kevin Knight. 2006.
Buttress
† Catholic_Encyclopedia ► Buttress
A pilaster, pier, or body of masonry projecting beyond the main face of the wall and intended to strengthen the wall at particular points and also to counterbalance the thrust of a roof or its vaulting. The term "counterfort" is used when the projection is on the inside. A flying buttress is an arch, resting at one end on a detached pier and it carries the thrust of the nave vault over the aisles or cloister.
THOMAS H. POOLE
The Catholic Encyclopedia, Volume VIII. — New York: Robert Appleton Company. Nihil Obstat. 1910.
Catholic encyclopedia.