A baseboard is a wooden, MDF, or vinyl board that covers the lowest part of an interior wall. It is installed at the joint between the wall surface and the floor and provides an attractive aesthetic element. Baseboards are usually between 3-8 inches wide and come in a variety of materials and profiles. They can be made up of a simple plank nailed, screwed, or glued to the wall, or they can be made up of a number of moldings for decoration. Baseboards differ from wainscoting, which typically covers from the floor to around 1-1.5 meters high, whereas a baseboard is typically under 0.2 meters high.

Baseboards come in a wide array of shapes and sizes, but they fall into just four trim profiles: rounded or stepped, flat, beaded, and grooved. Rounded or stepped baseboards are the most popular profile used in homes, and the top of the trim has a rounded shape that tapers into the wall. Flat baseboards are completely flat on the front and come in different heights, usually ranging from 3.5 inches to 4.5 inches. Beaded baseboards have a small groove or bead running along the top edge, while grooved baseboards have a channel or groove running along the top edge.

Baseboards are installed partly for aesthetic reasons, as they hide the joint where walls meet the floor, which might otherwise be unsightly. They also serve a necessary function in protecting plaster walls from getting kicked or scuffed by shoes, boots, and vacuum attachments. Baseboards can be made from a variety of materials, including solid hardwoods, engineered wood materials, medium-density fiberboard (MDF), plastic, and vinyl.

In summary, a baseboard is a decorative and functional element that covers the joint between the wall surface and the floor. It comes in a variety of materials, shapes, and sizes and is installed for aesthetic and protective purposes.