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

SCFAs, including butyrate, propionate, and acetate, support gut health by fueling the cells lining the large intestine, supporting intestinal mucus production, and reducing intestinal inflammation. —Jillian Kubala, Health, 30 Oct. 2025

Fortunately, the BreezyClear Pro is equipped to address all the baby’s needs from the beginning to the end of the decongestion process; by briefly misting the nasal passages, the device loosens mucus so its powerful suction can remove it quickly and without fuss. —Ethan Stone, USA Today, 28 Oct. 2025

The disease causes an overabundance of mucus, trapping infections and blocking airways in the lungs. —Katie Hunt, CNN Money, 4 Oct. 2025

Newborns and frail older people often have a hard time coughing up the mucus, Hopkins says. —Liz Szabo, Scientific American, 23 Sep. 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