gypsum lath, board lath, gypsum plaster-board, rock lath
A base for plaster; a sheet having a gypsum core, faced with paper, which provides a good bond for plaster; usually manufactured in 16-in. by 48-in. (40.6-cm by 121.9-cm) or 24-in. by 96-in. (61.0-cm by 243.8-cm) panels, ? or ½ in. (0.95 or 1.27 cm) thick with round or square edges.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.