aileron

Etymology

Borrowed from French aileron, diminutive of aile (“wing”), also refers to the extremities of a bird's wings used to control their flight. It first appeared in print in the 7th edition of Cassell's French-English Dictionary of 1877, with its lead meaning of "small wing". In the context of powered airplanes it appears in print about 1908, in the French aviation journal L'Aérophile.

noun

1. The hinged part on the trailing edge of an airplane wing, used to control longitudinal turns.
2. (architecture) A half gable, as at the end of a penthouse or of the aisle of a church.