The term 'BILLIARDS BORDER' is a crossword solution that consists of two words. The first word, 'RAIL', is a four-letter word that refers to the edge of a billiards table. The RAIL is the part of the table that surrounds the playing surface and is usually made of wood or metal. It is also known as the cushion, bumper, or band. The second word, 'BORDER', refers to the decorative trim that is placed around the edge of the table. This trim can be made of various materials such as wood, metal, or plastic and is used to give the table a finished look.