effacement

n. act of erasing, wiping out; destruction

Effacement is the shortening, or thinning, of the cervix before or during early labour. Prior to effacement, the cervix is like a long bottleneck, usually about four centimeters in length. Throughout pregnancy, the cervix is tightly closed and protected by a plug of mucus. When the cervix effaces, the mucus plug is loosened and passes out of the vagina. The mucus may be tinged with blood and the passage of the mucus plug is called bloody show (or simply "show").
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Noun
1. shortening of the uterine cervix and thinning of its walls as it is dilated during labor
(hypernym) organic process, biological process
(part-holonym) parturiency, labor, labour, confinement, lying-in, travail, childbed
2. withdrawing into the background; making yourself inconspicuous
(synonym) self-effacement
(hypernym) withdrawal
(derivation) efface

n. obliteration, effacing, erasing, deletion, wiping out, wipe, erasure, rub

(n.)
The act if effacing; also, the result of the act.