English UsageGrammar guide
Plural of Mumps
“Mumps” is an uncount disease noun and is conventionally used in that form rather than as the plural of a regular singular noun.
The disease name is “mumps”; it normally has no separate plural form.
Key details
Confusion Familynoun ending in s but uncount
Rule Familyplural and countability
Termsmumps
Variant ScopeThe disease name “mumps” is treated as an uncount/no-plural noun despite its final -s.
Further guidance
Core difference
“Mumps” is the disease name itself, not an ordinary count plural formed from a singular “mump.”
Fast Test
Use “mumps” as the disease name; do not create a separate regular singular/plural pair for ordinary modern usage.
Usage Boundary
The final -s does not by itself prove that an English noun is a grammatical plural.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- Mumps — Cambridge Dictionary (opens in a new tab)Cambridge University Press · Direct evidence that “mumps” is an uncount disease noun; Cambridge Essential also labels it no-plural.