baseboard

A functional and decorative element that is an essential part of interior finishing, it is the decorative strip that sits at the very bottom of a walls covering the junction where the wall and floor come together. It serves to protect walls, conceal imperfections, and add visual appeal to a room.

In some regions, baseboards might be called "skirting boards," "skirting," "wainscoting," "mopboard," "trim," "floor molding," or "base molding."