backboard

A flat, rigid, vertical board situated behind the rim of the basket and to which the basket is attached. Regulation backboards are made of plexiglass or tempered glass and are rectangular in shape, 6 feet (180 cm) wide by 3.5 feet (110 cm) tall, with a 24-by-18-inch (61 by 46 cm) rectangle marked on the glass immediately above the basket.