Quick answer
Moustache is the spelling to use in British English; mustache is the American version. Remember the extra o by thinking of moustache as the fuller, more traditional British spelling.
The core difference
The two words mean exactly the same thing; only the spelling changes between British and American English.
- moustache — hair grown on the upper lip, British spelling: Her grandfather has worn the same neat moustache for decades.
- mustache — the same hair, American spelling: He grew a mustache for charity in November.
How to tell them apart
Both forms come from French moustache, itself from Italian mostaccio, tracing back through Byzantine Greek to an ancient word for the upper lip. The British spelling kept the French "ou", while American English simplified it to "u".
The mix-up usually shows up in copy that has been drafted with American spellcheck defaults, where "mustache" slips into British-English text without anyone noticing.
Frequently asked questions
Do mustache and moustache have different meanings?
No, they refer to the same thing: hair grown on the upper lip. Only the spelling differs by region.
Which spelling should I use in a UK-facing article?
Moustache, to match standard British English.
Are they pronounced differently?
They are pronounced the same way; the spelling difference does not change how the word sounds.
