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

Adding to that challenge, the lung of a CF patient is filled with mucus. — Gerry Smith, CNBC, 9 Oct. 2026

Patients develop pneumonia and may show fever, headache, weakness, shortness of breath, chest pain, cough and bloody or watery mucus. — News Editor, CBS News, 6 Oct. 2026

Pneumonic plague can cause shortness of breath, chest pain, cough, and bloody or watery mucus, and pharyngeal plague can cause sore throat. — Tom Gavin, EverydayHealth.com, 6 Oct. 2026

Bacteria are also responsible for the mucus barrier along your gastrointestinal tract that prevents toxins from leeching into the bloodstream, Sullivan says. — Jackie Flynn Mogensen, Scientific American, 5 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