Petasos, also spelled Petasus, a wide-brimmed hat with a conical crown worn in ancient Greece. The petasos worn by men had a low crown, while that worn by women had a tall one. The petasos was made of felt or straw and had a chin strap. The winged hat of the god Hermes (or Mercury) pictured above was also called a petasos.
http://www.britannica.com/topic/petasos
Petasos, also spelled Petasus, a wide-brimmed hat with a conical crown worn in ancient Greece. The petasos worn by men had a low crown, while that worn by women had a tall one. The petasos was made of felt or straw and had a chin strap. The winged hat of the god Hermes (or Mercury) pictured above was also called a petasos.
http://www.britannica.com/topic/petasos