PILLION
pillion
(noun) a seat behind the rider of a horse or motorbike etc.
Source: WordNet® 3.1
Etymology
Noun
pillion (plural pillions)
A pad behind the saddle of a horse for a second rider.
A similar second saddle on a motorcycle for a passenger.
The person riding in the pillion.
The cushion of a saddle.
Adverb
pillion (comparative more pillion, superlative most pillion)
Riding behind the driving rider, as when positioned on the rump of a mount.
Verb
pillion (third-person singular simple present pillions, present participle pillioning, simple past and past participle pillioned)
To ride on a pillion.
To put a pillion on a horse.
Source: Wiktionary
Pil"lion, n. Etym: [Ir. pillin, pilliun (akin to Gael. pillean,
pillin), fr. Ir. & Gael. pill, peall, a skin or hide, prob. fr. L.
pellis. See Pell, n., Fell skin.]
Definition: A panel or cushion saddle; the under pad or cushion of saddle;
esp., a pad or cushion put on behind a man's saddle, on which a woman
may ride.
His [a soldier's] shank pillion without stirrups. Spenser.
Source: Webster’s Unabridged Dictionary 1913 Edition