The backboard in basketball is a piece of equipment where the hoop is attached to and used during shot attempts. There are markings on this board used to help players aim and perform bank shots. It is also known as the glass.
The backboards used in regulation competitions, such as high school, college, or professional basketball are made from plexiglass or tempered glass. Backboards were previously made of glass, but these were able to be shattered and thus were unsafe- just look at what Shaquille O'Neal did!
Backboards are 72 inches wide and 48 inches tall in a rectangular shape. The rim is positioned 12 inches up from the bottom of the backboard with a 24 by 18 inch box encompassing it, 10 feet above the floor.
The main purpose of the backboard is to stop shots from going past the basket and over the baseline, so that they can be rebounded or go into the basket on a bank. Without the backboard, shot attempts would constantly go out of bounds, rebounds would be much less frequent, and many shots would be less likely to go in.