Mucus vs. Mucous

Have you ever noticed these two different spellings of mucus? I, of course, have because I write about it all the time! As much as I love to learn and write about allergies and allergen avoidance, I love to learn about words. Today, I'm passing along a ‘fun’ fact about mucus versus mucous.

Simply put, mucus is a noun and mucous is an adjective. So, the actual fluid that comes out of your nose when you are congested is mucus and the linings in your body that secrete mucus are mucous membranes.'s definition of mucus is: ‘the slimy protective secretion of the mucous membranes, consisting mainly of mucin*.’ The word actually derives straight from the Latin word mucus, meaning ‘snot, slime, mold.’

Mucous, on the other hand, according to, is ‘pertaining to, consisting of, or resembling mucus’ or ‘containing or secreting mucus.’

Coming across it in the above definition of mucus, I had to look up the word mucin. Mucin is ‘any of a class of glycoproteins found in saliva, gastric juice, etc., that form viscous solutions and act as lubricants or protectants on external and internal surfaces of the body’ (

There you have it, folks, probably more than you ever wanted to know about mucus-related words. For more about mucus itself, stay tuned for February's allergist interview, in which Dr. Scott Carroll of the Atlanta Allergy and Asthma Clinic discusses what those different colors of mucus mean for your health.

6 thoughts on “Mucus vs. Mucous

  1. windy June 12, 2012 / 7:55 am

    I get it now. thank you!:D

  2. KevvyG September 3, 2013 / 8:05 am

    Though the spelling is different, the English pronounciation of mucus and mucous is the same. You are correct in noting the difference, but this is only when you pronounce it with the language from where the word originates – Latin.

  3. Adam September 6, 2013 / 1:54 am

    Concise! Thanks.

  4. Garima Srivastava May 29, 2014 / 6:44 am


  5. Brittany October 21, 2013 / 10:10 pm

    Perfect explanation. Thank you for clarifying!

  6. Kerrin October 8, 2014 / 7:27 am

    Thank you for clarifying this. I always wanted to know what was the difference between the two words. I appreciate this very much. Keep up the good work!

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