Source : Webster's Revised Unabridged Dictionary (1913)

Effacement \Ef*face"ment\, n. [Cf. F. effacement.]
   The act if effacing; also, the result of the act.

Source : WordNet®

effacement
     n 1: shortening of the uterine cervix and thinning of its walls
          as it is dilated during labor
     2: withdrawing into the background; making yourself
        inconspicuous [syn: {self-effacement}]