1. A block of any material, generally with little or no ornament, forming the lowest member of a base, or itself fulfilling the functions of a base, as a member applied to the foot of a door or to window trim.
2. A rectangular block at the base of a casing or column which the baseboard abuts; usually slightly thicker than either the casing or baseboard.
3. A skirting block.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.