A strip of wood or a metal bead used at an opening as a guide for plastering to a given thickness and as a stop for the plasterwork. 2. Anything used to fix a limit or to regulate the thickness or projection of the more permanent or of exterior finished work. The term is generally used in the plural; thus, grounds in ordinary building are pieces of wood secured to the jamb of a doorway, as in a brick wall, or to the base of a stud partition, to stop the plastering at the edge and to determine its thickness, and to these grounds the wooden trim may be nailed, or the grounds may be removed. Also, any strip secured to a wall, and more or less embedded in the plaster, to furnish a nailing, as to secure a wooden mantel, heavy trim, or the like. 3. A conducting connection between an electric circuit or device and the earth or other point of zero potential. 4. The receding part of a visual field against which a figure is perceived. Also called background.