Entry 1 sense Webster, 1913 Sombrero /säm-brĕr'-ō/ · Som·bre·ro · IPA /səmˈbɹɛɹ.oʊ/ 01 n. A kind of broad-brimmed hat, worn in Spain and in Spanish America. 1. A kind of broad-brimmed hat, worn in Spain and in Spanish America.