Sidewall

Noun

1. The side of a tire.

   "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."

2. The wall forming the side of a structure; a side wall. The wall forming the side of a racquetball court.
3. The wall forming the side of a racquetball court.