nominal size[′näm·ə·nəl ′sīz]
Size used for purposes of general identification; the actual size of a part will be approximately the same as the nominal size but need not be exactly the same; for example, a rod may be referred to as ¼ inch, although the actual dimension on the drawing is 0.2495 inch, and in this case ¼ inch is the nominal size.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The measurement used in naming a component, not necessarily its actual size when finished or milled. The size of timber is usually given in nominal size, and the actual size is slightly smaller, for example, a 2x4 actually measures 1 5/8 x 3 5/8 inches.
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved
The dimensions of sawn lumber before it is dried or surfaced. Also see dressed size.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.