mucus

noun

mu·​cus ˈmyü-kəs How to pronounce mucus (audio)
: 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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Even without actual mucus, suction cups with a water seal have been found to hang onto things 55 times longer than those without. ArsTechnica, 28 June 2025 This may look like blobs of mucus in the toilet or jelly-like strands of mucus on the stool. Sherri Gordon, Health, 21 June 2025 Drinking enough water can help thin mucus and ease breathing. Emily Brown, Verywell Health, 14 May 2025 Some infections that cause brown mucus include:6 Bacterial bronchitis: This bacterial lung infection causes brown or yellow-green mucus. Mark Gurarie, Health, 15 June 2025 See All Example Sentences for mucus

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

Time Traveler
The first known use of mucus was in 1597

Browse Nearby Words

Cite this Entry

“Mucus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mucus. Accessed 8 Jul. 2025.

Kids Definition

mucus

noun
mu·​cus ˈmyü-kəs How to pronounce mucus (audio)
: a slippery sticky substance produced especially by mucous membranes which it moistens and protects

Medical Definition

mucus

noun
mu·​cus ˈmyü-kəs How to pronounce mucus (audio)
: a viscid slippery secretion that is usually rich in mucins and is produced by mucous membranes which it moistens and protects

More from Merriam-Webster on mucus

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!