endothelium

noun

en·​do·​the·​li·​um ˌen-də-ˈthē-lē-əm 

-dō-

plural endothelia ˌen-də-ˈthē-lē-ə 

-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 

-dō-

adjective

Examples of endothelium in a Sentence

Recent Examples on the Web

The endothelium lines our vessels and is closely linked to vascular health. — Teresa Maalouf, Verywell Health, 12 June 2026

The virus appears to trigger a destructive host response in which infected endothelium, immune activation, platelets, coagulation, cytokine signaling, and complement converge to destabilize the vascular barrier. — Steve Brozak, Forbes.com, 15 May 2026

Such energy drinks can cause cardiac arrhythmias, damage the endothelium, the tissue that lines blood vessels, and aggregate blood platelets, Munshi said. — Cnn.com Wire Service, Mercury News, 10 Dec. 2025

Endothelial function refers to the healthy activity of the endothelium, a thin layer of cells lining the inside of blood vessels that regulates blood flow, prevents clotting, and controls inflammation. — Emily Kay Votruba, EverydayHealth.com, 3 Dec. 2025

When the inner lining (endothelium) leads gracefully and arteries stay limber, your cardiovascular health hits all the right notes. — Pranjal Malewar, New Atlas, 15 Oct. 2025

The virus that causes COVID can affect the vascular endothelium — specialized cells that line blood vessels and help with blood flow, Rasmussen said. — Kff Health News, San Diego Union-Tribune, 10 June 2025

Word History

Etymology

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

First Known Use

1872, in the meaning defined at sense 1

Rhymes for endothelium

• athenaeum
• coliseum
• colosseum
• mausoleum
• mycelium
• corneum
• hordeum
• luteum
• lyceum
• museum
• periosteum
• peritoneum

Medical Definition

endothelium

noun

en·​do·​the·​li·​um ˌen-də-ˈthē-lē-əm 

plural endothelia -lē-ə 

: 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)