What are a car's pillars?

Pillars are structural elements of a car's construction that connect the roof to lower areas of the body – the upright bits in between the windows and windscreens. The pillar that holds up the windscreen is called the A-pillar, the pillar behind the front door is the B-pillar, and the pillar behind the rear passenger seats is the C-pillar. Cars with a window behind the rear seats will also have a D-pillar, a fourth structural pillar that helps the car's rigidity and safety. Depending on the shape of the car, either the C or D-pillar will hold the rear windscreen in place.