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Descriptive of a mortar joint in a brick wall used in the early 19th century when extremely thin mortar joints were fashionable. They were prepared as follows: First, the wall, with mortar joints flush with the brick surface, was painted the color of the brick; then a narrow white line painted along the center of the mortar joints.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.