A baseboard is a board running the length of a wall, at the base--thus, baseboard.

Purpose

The baseboard serves to cover up the gap between floor and the bottom end of the drywall (because drywall is purposely not resting directly on the floor but is about half an inch higher than the floor).

Sizes

Baseboard typically ranges from 1 1/2" to 5 1/4" high; is composed of wood or plastic; and usually is painted white.

The installation of baseboards is a type of finish carpentry.