Also found in: Dictionary.
1. To make the surface of some object smooth or devoid of something with an abrasive material, especially sandpaper. A noun or pronoun can be used between "sand" and "down." The carving could give you splinters if you don't sand down the edges. I need to sand this old table down before I can apply a new coat of paint on it, or the old color will keep peeking through.
2. To remove something from the surface of some object with an abrasive material, especially sandpaper. A noun or pronoun can be used between "sand" and "down." I want to sand down the notches the previous owner made into this bannister. We should be able to sand those down to where you won't even notice them.
sand something down
1. to make something smooth by rubbing it with sandpaper. (To act on the main body of the object, not the imperfections.) You should sand the board down before you paint it. Please sand down the board.
2. to remove bumps or imperfections on the surface of something by rubbing them with sandpaper. (To act on the imperfections, not the main body of the object.) Sand these bumps down, will you? Sand down these bumps, please.