petasos
noun
pet·a·sos ˈpe-tə-səs 
variants or petasus
: a broad-brimmed low-crowned hat worn by ancient Greeks and Romans
especially : the winged hat of Hermes
Word History
Etymology
Latin & Greek; Latin petasus, from Greek petasos; akin to Greek petannynai to spread out
First Known Use
1577, in the meaning defined above