mucus

noun

mu·​cus ˈmyü-kəs 

: a viscid slippery secretion that is usually rich in mucins and is produced by mucous membranes which it moistens and protects

Examples of mucus in a Sentence

Recent Examples on the Web

Causes of Sneezing Sneezing is caused by the irritation of the mucus membranes in the nose or throat. —Valerie Cacho, Verywell Health, 29 July 2025

This finding prompted their primary care physician to order tests for cystic fibrosis (CF), a genetic disorder that causes thick, sticky mucus to build up in the lungs, digestive system and other organs. —Jordan Greene, People.com, 24 June 2025

These and more than 200 other viruses spread through saliva or mucus particles expelled from a sick person. —Daryl Austin, USA Today, 12 June 2025

Patients develop fever, headache, weakness and pneumonia with shortness of breath, chest pain, cough and sometimes bloody or watery mucus. —Saleen Martin, USA Today, 11 July 2025

Word History

Etymology

borrowed from Latin mūcus, muccus "nasal discharge," perhaps going back to *moukos, o-grade derivative of Indo-European *(s)muk- "nasal discharge," *(s)meuk- "undo, loosen, wipe off" — more at myxo-

Note: See note at myxo-.

First Known Use

1597, in the meaning defined above

Rhymes for mucus

• fucus
• mucous
• caducous
• sambucus
• submucous
• verrucous

Kids Definition

mucus

noun

mu·​cus ˈmyü-kəs 

: a slippery sticky substance produced especially by mucous membranes which it moistens and protects

Medical Definition

mucus

noun

mu·​cus ˈmyü-kəs 

: a viscid slippery secretion that is usually rich in mucins and is produced by mucous membranes which it moistens and protects