\Pil"lion\, n. [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.]
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.