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

The child, who had been choking on mucus, was taken to Jacobi Hospital as a precaution and is doing well, police said. —Stephen Sorace, FOXNews.com, 1 Feb. 2026

If the infection is not contained by the body’s immune response, the bacteria destroys lung tissue which can trigger chest pain and coughing up of mucus or blood. —Chase Hunter, Mercury News, 31 Jan. 2026

In fact, many of your symptoms like mucus production are actually your immune system’s reactions to the virus. —Bruce Y. Lee, Forbes.com, 24 Jan. 2026

So, measles showing up in wastewater is a sign that infected people are shedding tiny bits of the virus through things like mucus, saliva and stool. —Charlotte Observer, 23 Jan. 2026

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