(1):

(n.) The last joint, or bend, of the wing of a bird.

(2):

(n.) The small distortion of an astronomical instrument caused by the weight of its parts; the amount to be added or substracted from the observed readings of the instrument to correct them for this distortion.

(3):

(n.) A turn; a bend; a fold; a curve.

(4):

(n.) The act of flexing or bending; a turning or curving; flexion; hence, obsequious bowing or bending.