D defs.my
Entry 4 senses Webster, 1913

Flexion

/flĕk'-shən/ · Flex·ion · IPA /ˈflɛk.ʃən/
01 n. The act of flexing or bending; a turning.
  1. 1.
    The act of flexing or bending; a turning.
  2. 2.
    A bending; a part bent; a fold.
  3. 3.
    Syntactical change of form of words, as by declension or conjugation; inflection.(Gram.)
    “Express the syntactical relations by flexion.” Sir W. Hamilton.
  4. 4.
    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.(Physiol.)