Pillars refer to the vertical or near-vertical pillars supporting the windshield or the car's greenhouse, referred to as the A, B, C, or (in larger cars) D-pillars, from front to rear.
The consistent alphabetical designations of a car's pillars provide a common reference for design discussion and critical communication.
- The B pillars are referred to as the posts. The pillar is typically a closed steel structure welded at the bottom to the car's rocker panel and floorpan as well as on the top to the rail roof panel. This pillar provides structural support for the vehicles' roof panel and is designed for latching the front door and mounting hinges for the rear doors.
- Closed vehicles without a B pillar are widely called as hardtops and have been available in two or four-door body styles.