The greenhouse of a vehicle is the “glassed” area above the fender line. This comprises the windshield, rear and side windows, and, incidentally, any pillars separating them.^[1][2]

The shape and position of the greenhouse have a defining influence on the looks and functionality 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 became narrower because of design trends and crash regulations.^{[citation needed]}