Five more weird car design terms, explained

Automobile designers speak in a “code,” composed of terms borrowed from other fields and curious anatomical references, with the odd made-up acronym sprinkled here and there.

The 1998 Audi TT is a milestone in recent car design history (illustration from the Author)

Using my little sketch of the seminal 1998 Audi TT, I’ll guide you through five weird terms used in automobile design, starting with…

Greenhouse

The glazed surfaces of a car’s body make up the “greenhouse” (illustration from the Author)

Although cars aren’t typically used to grow flowers or vegetables, the glazed area of an automobile is called “greenhouse,” and that’s rather apt, as whoever left a car parked under the summer sun will know.

Tumblehome

The way a car’s cross-section slopes inward is called “tumblehome” (illustration from the Author)

This rather funky word originated in the marine sector, but car designers use it to define a vehicle’s side windows’ inward curvature.
Pretty much all passenger cars nowadays feature curved side glass, and tumblehome can get pretty extreme on high-end sports cars to optimize their cross-section for aerodynamic purposes. On cargo vans, tumblehome is minimal or non-existent, to maximize interior volume relative to exterior size.

Overhang

Overhangs are among car designer’s worse enemies… (illustration from the Author)

The part of the vehicle that extends ahead of the front wheels’ centerline or behind the rear wheels’ one is called “overhang.”
Designers usually seek to minimize overhangs, but that’s not always possible, as it depends on the vehicle’s technical layout and mission.

Character Line

Any line that’s only there for looks is a “character line” (illustration from the Author)