ENDOMETRIUM

n. membrane which lines the uterus

The endometrium is the inner membrane of the mammalian uterus.
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Endometrium /en·do·me·tri·um/ pl. endome´tria the mucous membrane lining the uterus. en·do·me·tri·um n. pl. [more]Endometrium - Community and Resources

Noun
1. (pregnancy) the mucous membrane that lines the uterus; thickens under hormonal control and (if pregnancy does not occur) is shed in menstruation; if pregnancy occurs it is shed along with the placenta at parturition
(hypernym) mucous membrane, mucosa
(part-holonym) uterus, womb
(substance-meronym) decidua
(classification) pregnancy, gestation, maternity

n. endometrium, membrane which lines the uterus