(1):

(n.) The act of flexing or bending; a turning.

(2):

(n.) The bending of a limb or joint; that motion of a joint which gives the distal member a continually decreasing angle with the axis of the proximal part; - distinguished from extension.

(3):

(n.) Syntactical change of form of words, as by declension or conjugation; inflection.

(4):

(n.) A bending; a part bent; a fold.