sidewall

side +‎ wall.

sidewall (plural sidewalls)

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.
   1. The wall forming the side of a racquetball court.
      • 1978, Charles Garfinkel, Racquetball the easy way‎, page 87:

        The kill shot may also be used against balls weakly played off the sidewall

      • 2003, David Waters, February the Sixth‎, page 53:

        Mark flipped the ball to Jon for service. His high serve drifted perfectly down the left-hand court, and Mark's weakly hit return fell short off the sidewall.

      • 2009, Allan D. Moore, Doms Need Love Too!: Adventures of the Day Old Muffins‎, page 116:

        Further, the grazing blow caused the ball to pick up a furiously wicked spin, making it a madly twirling object. The ball skimmed off the sidewall near the corner and into the lower-right corner of the front wall.

• wallside, well said