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1. One or more courses of tiles or bricks laid upon the top of a wall or chimney with a projection of 1 to 2 in. (2.5 to 5 cm) for each course over the one below, to throw off water; if there is coping, it is placed above the creasing. Also called a creasing course, tile creasing.
2. A layer of slates or of metal over a projecting string-course or window cap, serving as a flashing to prevent the infiltration of moisture.