en·​do·​me·​tri·​um | \ˌen-dō-ˈmē-trē-əm \
plural endometria\ ˌen-​dō-​ˈmē-​trē-​əm \

Definition of endometrium 

: the mucous membrane lining the uterus

Keep scrolling for more

Other Words from endometrium

endometrial \ ˌen-​dō-​ˈmē-​trē-​əl \ adjective

Examples of endometrium in a Sentence

Recent Examples on the Web

In general, most experts go with the definition shared by the Mayo Clinic, which describes it as a painful disorder in which tissue that normally lines the inside of your uterus (the endometrium) grows outside your uterus. Korin Miller, SELF, "Halsey Is Freezing Her Eggs at Age 23 Due to Her Endometriosis and Previous Miscarriage," 27 Apr. 2018 These nonhormonal early versions probably worked by interfering with ovulation, fertilization, or implantation by causing mild inflammation of the endometrium. Carolyn Todd, Allure, "The History and Evolution of Birth Control in America," 12 July 2018 As women age, the endometrium tends to thin, and the rate of IVF failure increases. Kate Morgan, The Cut, "Viagra’s Other Life as a Female Fertility Aid," 27 Mar. 2018 Uterine polyps: These are growths that pop up in your endometrium, per the Cleveland Clinic. Korin Miller, SELF, "How Long Does a Period Last, Normally?," 17 May 2018 The leading theory During a woman’s monthly menstrual cycle, hormones signal the endometrium to thicken. Marie Mccullough, Philly.com, "Frustrated endometriosis patients fuel surge in activism while seeking answers," 12 Apr. 2018 In 1989, Sher had published research examining the correlation between the thickness of a woman’s endometrium — the uterine lining — and the successful implantation of an embryo through IVF. Kate Morgan, The Cut, "Viagra’s Other Life as a Female Fertility Aid," 27 Mar. 2018 The system comprises mouse ovarian cells (which produce the same hormones as human ovaries), along with human cells from the fallopian tube, endometrium and cervix. Dina Fine Maron, Scientific American, "Menstrual Cycle “on a Chip” Offers a New Window into Female Physiology," 1 June 2017 More recently, doctors have argued that the tissue is made up of something similar in nature to the endometrium, but genetically different. Abby Haglage, SELF, "This 3-D Tissue Culturing System Could Change the Way Doctors Treat Endometriosis," 25 Oct. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'endometrium.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of endometrium

circa 1882, in the meaning defined above

History and Etymology for endometrium

New Latin, from end- + Greek mētra uterus, from mētr-, mētēr mother — more at mother

Keep scrolling for more

Learn More about endometrium

Share endometrium

Statistics for endometrium

Last Updated

12 Oct 2018

Look-up Popularity

Time Traveler for endometrium

The first known use of endometrium was circa 1882

See more words from the same year

Keep scrolling for more

More Definitions for endometrium


en·​do·​me·​tri·​um | \-ˈmē-trē-əm \
plural endometria\ -​trē-​ə \

Medical Definition of endometrium 

: the mucous membrane lining the uterus that is composed of three layers — see stratum basale, stratum compactum, stratum spongiosum

More from Merriam-Webster on endometrium

Britannica.com: Encyclopedia article about endometrium

Comments on endometrium

What made you want to look up endometrium? Please tell us where you read or heard it (including the quote, if possible).


a private place of worship

Get Word of the Day daily email!

Test Your Vocabulary

Difficult Vocab Quiz

  • the-education-of-achilles-eugne-delacroix
  • Which is a synonym of discomfit?
Name That Thing

Test your visual vocabulary with our 10-question challenge!

Syn City

Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!