Basin

1. An open, shallow, usually round container used especially for holding liquids. She put warm water in the basin and washed her hair.
2. A washbowl; a sink. We have two basins in our master bathroom.
3. A region drained by a single river system. The Amazon basin covers over three million square miles.
4. A large, bowl-shaped depression in the surface of the land or ocean floor. The Los Angeles basin is known for its persistent smog.