Home › Words › M › milkstachemilkstachemilkstache · noun — the residue left upon the upper lip area after drinking milk, a milkshake, foamy coffee, etc.Definition from Wiktionary (CC BY-SA 3.0).EtymologyBlend of milk + moustache.nounThe residue left upon the upper lip area after drinking milk, a milkshake, foamy coffee, etc.Definitions & examples from Wiktionary (CC BY-SA 3.0).