Flexion

Webster's Dictionary of the English Language

·noun A bending; a part bent; a fold.

II. Flexion ·noun The act of flexing or bending; a turning.

III. Flexion ·noun Syntactical change of form of words, as by declension or conjugation; inflection.

IV. Flexion ·noun 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.