English homophones
mucous/mucus
"mucous" is an adjective; "mucus" is a noun - grammar picks the spelling, not sound. Size rank #133 of 1,007 English groups.
Data vintage
Grammar picks the spelling
Same sound, different grammar: "mucous" arrives as an adjective, while "mucus" is a noun. Once the sentence role is fixed, only one spelling fits.
Spelling pairs in this cluster
- Shared stem "muc" then splits - "mucous" (6 letters) vs "mucus" (5).
Orthographic DNA of this cluster
Shared letters across mucous, mucus: cmsu. Private letters are the ones only one spelling owns: the eye's fastest tell once sound is out of the picture.
mucous
6 letters · 3 vowels · shape CVCVVC
Inventory cmosu · private o
mucus
5 letters · 2 vowels · shape CVCVC
Inventory cmsu · no private letters vs siblings
Pick the spelling from the meaning
- Write "mucous" when you mean: Pertaining to mucus.
- Write "mucus" when you mean: A slippery secretion from the lining of the mucous membranes.
Known mistypes of these spellings
Edit-distance variants recorded against this cluster: useful when a search or OCR feed lands on the wrong form.
Each spelling
Nearby English homophone groups
What to do next
You've reviewed the 2-spelling cluster (mucous, mucus). Here's where to go from here.
- "mucus" is the most frequent headword in this 2-spelling cluster (rank #23,915 in English). Full entry
- Among English homophone groups, a cluster of 2 spellings ranks #133 by size (1,007 groups in this vintage). Corpus statistics
- Explore a nearby 2-spelling cluster: mall · maul. Nearby cluster
- Grammar often disambiguates this cluster, match the meaning to the part of speech before picking a spelling. Pick by meaning
PlainSpell is a reference corpus, not spelling advice. Verify unusual forms in context.