A wing.

(ornithology) The joint of a bird's wing farthest from the body.

(ornithology) Any of the outermost primary feathers on a bird's wing.

A moth of the genus Lithophane.

(mechanical engineering) The smallest gear in a gear train.

To cut off the pinion of a bird’s wing, or otherwise disable or bind its wings, in order to prevent it from flying.

To bind the arms of someone, so as to deprive him of their use; to disable by so binding.

(transferred sense, figurative) To restrain; to limit.