v.1. To cleanse the surface of something using water or other liquid: We washed down the walls. My neighbor washed the car down.
2. To cause something to be carried or drawn down by the action of water or similar liquid: We tried to wash the grease down, but it stuck to the sides. I washed the tar down with the hose.
3. To follow the ingestion of something, such as food, with the ingestion of a liquid: After the party, we washed the cake down with coffee. I washed down the medicine with some juice.