1. A molding or board placed along the bottom of a wall next to the floor; also called Baseboard. 2. A vinyl, wood or metal trim applied at the floor line to protect the vertical wall from damage. 3. The bottom of a column. 4. One or more rows of tile installed above the floor. 5. See Plaster Base. 6. The lowest part, or the lowest main division, of a building, column, pier, or wall. 7. The lowest point of any vertical pipe.