noun

1. A pad behind the saddle of a horse for a second rider.

2. A similar second saddle on a motorcycle for a passenger.

3. The person riding in the pillion.

Synonyms: pillionist

verb

1. To ride on a pillion.

2. To put a pillion on a horse.

adverb

1. Riding behind the driving rider, as when positioned on the rump of a mount.