Mucous or mucus?
mucous is an adjective meaning “Pertaining to mucus”; mucus is a noun meaning “A slippery secretion from the lining of the mucous membranes”. Use mucous as an adjective and mucus as a noun. They sound the same (/ˈmjuːkəs/). In written English (wordfreq, 2021 data) mucus is about 2.5 times as common as mucous.
What is the difference between mucous and mucus?
| mucous | mucus | |
|---|---|---|
| Part of speech | adjective | noun |
| Meaning | Pertaining to mucus Having the qualities of mucus; resembling mucus | A slippery secretion from the lining of the mucous membranes |
| Example | none recorded | The mucus in coryza may vary from runny to viscous |
| Forms | none | muci, mucuses |
| Pronunciation | /ˈmjuːkəs/ | /ˈmjuːkəs/ |
| In writing | about once in every 2 million words | 1.4 times per million words |
Sources: mucous and mucus in the English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0); written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
Every current meaning of mucous and mucus
mucous
- 1
Pertaining to mucus
- 2
Having the qualities of mucus; resembling mucus
mucus
- 1
A slippery secretion from the lining of the mucous membranes
The mucus in coryza may vary from runny to viscous
- 2
Short for vegetable mucus
Source: the English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0); obsolete, archaic, dialect and rare senses left out.
Which is more common, mucous or mucus?
mucous appears about once in every 2 million words; mucus 1.4 times per million words.
mucous about once in every 2 million wordsmucus 1.4 times per million words
Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
How many people search mucous vs mucus?
“mucous vs mucus” is searched about 1,600 times a month on Google and 30 on Bing in the United States. Google counts close variants of a query together (“mucus vs mucous”, “mucous or mucus”).
Sources: Google Ads keyword data through DataForSEO and Microsoft Advertising keyword data through DataForSEO, the average month from September 2025 to August 2026.