noun. The glandular mucous membrane that lines the uterus.

noun. The lining membrane of the uterus.

noun. The membrane lining the inner surface of the uterus, or womb.

noun. the mucous membrane that lines the uterus in mammals and in which fertilized eggs are implanted

noun. (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

"Ninety-four percent of uterine cancers begin in the lining of the uterus, also called the endometrium."