Plural of mustache: facial hair that grows on the upper lip above the mouth.
From French 'moustache,' from Italian 'mostaccio,' from Greek 'mystax' (upper lip). The word traveled European languages, shifting in spelling as it was borrowed.
Mustaches have been so culturally important that they've triggered wars—the Ottoman Empire required mustaches as a sign of status, and losing one could mean serious social disgrace!
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