I. ˈpil-yən noun
Etymology: Scottish Gaelic or Irish; Scottish Gaelic pillean, diminutive of peall covering, couch; Irish pillín, diminutive of peall covering, couch
Date: 1503
1.
a. : a light saddle for women consisting chiefly of a cushion
b. : a pad or cushion put on behind a man's saddle chiefly for a woman to ride on
2. chiefly British : a motorcycle or bicycle saddle for a passenger
II. adverb
Date: 1926
chiefly British : on or as if on a pillion
ride pillion