endothelium

noun

en·​do·​the·​li·​um ˌen-də-ˈthē-lē-əm How to pronounce endothelium (audio)
-dō-
plural endothelia ˌen-də-ˈthē-lē-ə How to pronounce endothelium (audio)
-dō-
1
: an epithelium of mesodermal origin composed of a single layer of thin flattened cells that lines internal body cavities and the lumens of vessels
2
: the inner layer of the seed coat of some plants
endothelial
ˌen-də-ˈthē-lē-əl How to pronounce endothelium (audio)
-dō-
adjective

Examples of endothelium in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Aging and menopause contribute to the dysfunction of the endothelium (cells of blood vessels). — Merve Ceylan, Health, 27 Dec. 2024 These complexes establish productive cellular infections in macrophages that result in the release of high concentrations of toxic NS1, a viral protein that damages cells' endothelium and produces dengue shock syndrome. — Scientific American, 1 Jan. 2024

Word History

Etymology

New Latin, from end- + -thelium (as in epithelium)

First Known Use

1872, in the meaning defined at sense 1

Time Traveler
The first known use of endothelium was in 1872

Rhymes for endothelium

See All Rhymes for endothelium

Browse Nearby Words

endothelioma
endothelium
endotherm
See all Nearby Words

Cite this Entry

“Endothelium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/endothelium. Accessed 26 Mar. 2025.

Copy Citation

Share

Medical Definition

endothelium

noun
en·​do·​the·​li·​um ˌen-də-ˈthē-lē-əm How to pronounce endothelium (audio)
plural endothelia -lē-ə How to pronounce endothelium (audio)
: an epithelium of mesoblastic origin composed of a single layer of thin flattened cells that lines internal body cavities (as the serous cavities or the interior of the heart)

More from Merriam-Webster on endothelium

Britannica.com: Encyclopedia article about endothelium

Love words? Need even more definitions?

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

Popular in Grammar & Usage

See More

How to Use Em Dashes (—), En Dashes (–) , and Hyphens (-)

The Difference Between 'i.e.' and 'e.g.'

Why is '-ed' sometimes pronounced at the end of a word?

Words You Always Have to Look Up

Democracy or Republic: What's the difference?
See More

Popular in Wordplay

See More

Top 10 Sophisticated Insults

Flower Etymologies For Your Spring Garden

More Words with Remarkable Origins

Terroir, Oenophile, & Magnum: Ten Words About Wine

8 Words for Lesser-Known Musical Instruments
See More

Popular

See More

How to Use Em Dashes (—), En Dashes (–) , and Hyphens (-)

Top 10 Sophisticated Insults

Flower Etymologies For Your Spring Garden
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Word Game Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
Missing Letter A daily crossword with a twist
dog-in-disguise
Rhyme Disguise Quiz Pair up words that look different but sound alike.
See All