deflection (n.)

also (and with more etymological propriety) deflexion, "act of turning or state of being turned aside," c. 1600, from Latin deflexionem, noun of action from past-participle stem of Latin deflectere "to bend (something) aside or downward," from de "away" (see de-) + flectere "to bend," which is of uncertain origin. Both forms were in use in 17c., but since then the spelling with -c- has come to predominate.