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

In the human intestine, microorganisms are concentrated mainly in a mucus layer near the villi’s surface. — Neetika Walter, Interesting Engineering, 15 Oct. 2026

Lung adenocarcinoma begins in cells in the lung that make mucus, called epithelial cells, which line the surface of the lungs, the American Cancer Society says. — ABC News, 15 Oct. 2026

Guaifenesin may help relieve chest congestion by thinning mucus in your airways, says Reed. — Andee Tagle, NPR, 15 Oct. 2026

Adding to that challenge, the lung of a CF patient is filled with mucus. — Gerry Smith, CNBC, 9 Oct. 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

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