Any lumber which has been edge-dressed and shaped to make a tongue-and-groove joint on the edges when laid edge to edge.
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved
Lumber having dressed edges and prepared for tongue-and-groove joints.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.