sidewall
The side of a tire.
Example
“If the puncture had been in the tread I could have had the tire patched, but it was in the sidewall and they can't fix that: they have to replace the whole tire.”
Other meanings
The wall forming the side of a structure; a side wall.
The wall forming the side of a racquetball court.
Where this comes from
This definition is adapted from “sidewall” on Wiktionary, by its contributors, published under CC BY-SA 4.0. This page is published under the same licence.