mucus

American  

[myoo-kuhs] / ˈmju kəs /

noun

1. a viscous, slimy mixture of mucins, water, electrolytes, epithelial cells, and leukocytes that is secreted by glands lining the nasal, esophageal, and other body cavities and serves primarily to protect and lubricate surfaces.

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mucus British  

/ ˈmjuːkəs /

noun

1. the slimy protective secretion of the mucous membranes, consisting mainly of mucin

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mucus Scientific  

/ myo̅o̅′kəs /

1. The slimy, viscous substance secreted as a protective lubricant by mucous membranes. Mucus is composed chiefly of large glycoproteins called mucins and inorganic salts suspended in water.

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mucus Cultural  

1. A slippery and somewhat sticky fluid secreted by the glands in mucous membranes. Mucus lubricates and protects the mucous membranes.

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Etymology

Origin of mucus

1655–65; < Latin mūcus snot; akin to Greek myktḗr nose, mýxa slime

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Compare meaning

How does mucus compare to similar and commonly confused words? Explore the most common comparisons:

• sputum vs. mucus

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Explanation

Mucus is snot and other slime from inside your body. More specifically, mucus is a secretion of your body's mucus membranes that lubricates the inside of your body and helps protect you from bacteria. You’re welcome. Even the history of the word mucus is gross — roots from Greek and Latin all mean “snot” and “slippery, slimy.” Mucus drips out of your nose and even slips down your throat when you’re sick. This happens because your membranes produce too much mucus when you’re sick. Mucus isn’t all bad though — your body uses it to help food go down your throat easier, and it keeps bacteria out. Mucus is gross, but germs are worse!

Example Sentences

See Examples For:

mucus

Adenocarcinomas develop in cells that produce mucus and are one of the most common types of lung cancer.

From BBC ● Oct. 14, 2026

Patients quickly develop a fever and headache and feel weak, and then rapidly progress to shortness of breath, chest pain, cough and sometimes bloody or watery mucus, according to the CDC.

From The Wall Street Journal ● Oct. 6, 2026

They found that the "bad" phenols were produced when bacteria consumed proteins from the host, including proteins found in the mucus lining of the gut.

From Science Daily ● Aug. 15, 2026

When Howard was seven years old, he was diagnosed with cystic fibrosis, the genetic condition that causes sticky mucus to build up in the lungs and digestive system.

From BBC ● Jul. 14, 2026

I breathe in again, though it definitely makes me feel like the hot dog I ate earlier is going to join ump guy’s blob of mucus beside me.

From "Fast Pitch" by Nic Stone

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Related Words

• goo
• gunk
• mud
• sludge

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