Picture molding, also known as picture rail or dado rail, is a decorative trim that runs along the uppermost part of a room's wall. It is used to hang pictures or other decorative items without having to make holes in the wall. While 'picture molding' is the most common term, there are several synonyms that refer to the same element. Examples include 'picture rail molding', 'art rail', 'hanging rail', 'picture ledge molding', and 'plate rail'. These terms are often used interchangeably, and while they may differ slightly in style or size, they all provide the same practical functionality and aesthetic appeal to a room's decor.