Aileron /(ā"lē̇*rŏn)/

Ai·le·ron

Aileron

n.
  1. A half gable, as at the end of a penthouse or of the aisle of a church.
  2. 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. (Aëronautics)