mustache cup vs moustache cup

mustache cup and moustache cup both are nouns.

Word	Noun	Adjective	Verb	Adverb
mustache cup	Yes	No	No	No
moustache cup	Yes	No	No	No

As nouns, mustache cup and moustache cup are synonyms defined as:

mustache cup and moustache cup: a drinking cup with a bar inside the rim to keep a man's mustache out of the drink

mustache cup (noun)	moustache cup (noun)
a drinking cup with a bar inside the rim to keep a man's mustache out of the drink	a drinking cup with a bar inside the rim to keep a man's mustache out of the drink