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

Direct contact with mpox rash or scabs, as well as contaminated bodily fluids — like mucus, saliva or blood — are the most common ways people pass the virus to each other. —Mary Walrath-Holdridge, USA Today, 10 Dec. 2025

Symptoms include headache, muscle ache, and high fever in the initial phase, followed by coughing, which can bring up mucus or even blood, shortness of breath, chest pain, nausea, diarrhea, and confusion or other mental changes. —Peter Aitken, MSNBC Newsweek, 6 Dec. 2025

That slower flow of air means that there’s more time for slowly-absorbing chemicals to dissolve into the mucus lining. —Sarah Philip, Popular Science, 4 Dec. 2025

Early in a cold, your mucus might be clear or slightly cloudy. —Health, 3 Dec. 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