Baseboard is a type of trim that is installed at the bottom of a wall, where it meets the floor. It is used to cover gaps between the drywall/plaster and the flooring, and to protect the wall material from wear and tear. It should be chosen to work with your casing to finish and tie the room together. Baseboards are usually thinner than the casing, and creates a smooth transition from the wall to the floor, guiding you seamlessly from room to room.