1. the side surface of a tire between the tread and the rim
2. a wall that forms the side of a structure or enclosure

Examples

• The tire’s sidewall was damaged by the sharp curb.
• Check the sidewall for the tire’s pressure rating.
• The basketball hit the sidewall of the court.
• Workers reinforced the sidewall of the tunnel.
• The sidewall of the building needed repair after the storm.
• She noticed a bulge in the tire’s sidewall.
• The racquetball bounced off the sidewall at an angle.