The word "sidewall" refers to the vertical side of something, like a tire or a building. It is the part that runs from the bottom to the top and helps provide structure and support. Full definition
The taller tire sidewalls of the LT ate up more undulations than the thinner rubber on the Premier, but all that tire led to plenty of road noise making its way into the cabin below highway speeds. (cnet.com)
Give me the extra tire sidewall of 17 - inch wheels, man. (bestride.com)
«Touch input on sidewalls in device 10 may be used as a control for a camera (e.g., a virtual shutter button input), may be used as input in other virtual button scenarios, may be used in implementing a volume slider button or a slider button for controlling other device operations (e.g., screen brightness, color settings, contrast settings, etc.),» Apple notes. (bgr.com)