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

Their wavelike motion helps move around germs, mucus, dust, and other irritants so the body can dispel them via coughing or sneezing. — Jennifer Ouellette, ArsTechnica, 18 Sep. 2026

Diagnosed at age 3 with cystic fibrosis, a genetic disease that clogs the lungs with sticky mucus, Smith grew up with doctors expecting a cure to arrive in time to save her. — Laura Sharman, CNN Money, 9 Sep. 2026

AstraZeneca's drug works by blocking a protein called IL-33 that drives inflammation and mucus production, two of the underlying disease drivers of COPD. — Annika Kim Constantino, CNBC, 8 Sep. 2026

Bowel movements should also be relatively consistent and free of blood, mucus or foreign material. — Lauren Paige Richeson, USA Today, 19 Aug. 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