Source : Webster's Revised Unabridged Dictionary (1913)

Retroflexion \Re`tro*flex"ion\, n.
   The act of reflexing; the state of being retroflexed. Cf.
   {Retroversion}.

Source : WordNet®

retroflexion
     n 1: a turning or tilting backward of an organ or body part;
          "retroversion of the uterus" [syn: {retroversion}, {retroflection}]
     2: an articulatory gesture made by turning the tip of the
        tongue back against the roof of the mouth [syn: {retroflection}]
     3: the act of bending backward [syn: {retroflection}]