aileron

n. [ F., dim. of aile wing. ] 1. A half gable, as at the end of a penthouse or of the aisle of a church. [ Webster 1913 Suppl. ]

2. (Aëronautics) A small plane or surface capable of being manipulated by the pilot of a flying machine to control lateral balance; a hinged wing tip; a lateral stabilizing or balancing plane. [ Webster 1913 Suppl. ]