Sidecar (noun)

1. A small one-wheeled vehicle attached to the side of a motorcycle for carrying a passenger.
2. A small auxiliary car attached to a main vehicle, used especially to transport people with disabilities.

Origin:

Mid 19th century; earliest use found in the illustrated london news. short for side-carriage.

Examples:

1. He drove down the road with his girlfriend in the sidecar of his motorcycle.
2. The sidecar was adapted for transporting a wheelchair and made it easier for the disabled person to go on long drives.