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The greenhouse (or glasshouse) of a car comprises the windshield, rear and side windows, the pillars separating them (designated A-pillar, B-pillar and so on, starting from the car's front), and the car's roof.
The shape and position of the greenhouse have a defining influence on the looks of the car and are a prime factor in differentiating between body styles such as saloon/sedan, coupé, estate/wagon and hatchback. A greenhouse with noticeably inward side slopes is also referred to as the tumblehome.
In the 2000s and 2010s, greenhouses have become narrower because of design trends and crash regulations.