Pronunciation: (môr'tur-bôrd", -bōrd"), [key]
1. a board, usually square, used by masons to hold mortar.
2. Also called cap. a cap with a close-fitting crown surmounted by a stiff, flat, square piece from which a tassel hangs, worn as part of academic costume.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.