From Longman Dictionary of Contemporary Englishsombrerosom‧bre‧ro /sɒmˈbreərəʊ $ sɑːmˈbreroʊ/ noun (plural sombreros) [countable] 
DCCa Mexican hat for men that is tall with a wide round brim1 turned up at the edges
DCCa Mexican hat for men that is tall with a wide round brim1 turned up at the edgesExamples from the Corpus
sombrero• He wore a suit, and had a sombrero, and looked like the owner of a hacienda.• I've seen several big sombreros which are unusual and rather pretty.• Amin was wearing an electric-blue safari suit with matching sombrero.• They wear square hats, when they should try sombreros.• Leaders wear sombreros and opt for education.Origin sombrero (1500-1600) Spanish sombra “shade” 