Definition of "endometrium" [en•do•me•tri•um]

• The glandular mucous membrane that lines the uterus. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Ninety-four percent of uterine cancers begin in the lining of the uterus, also called the endometrium."
• "In a natural anticipation of fertilization, these rising estrogen levels stimulate the tissue that lines the inside of your uterus called the endometrium to begin growing thicker."
• "The entire cavity of the uterus is lined by a mucous membrane; [1] this mucous membrane is called the endometrium (endo -- within; metra -- uterus)."