from The Century Dictionary.
- noun In Greek antiquity, a low-crowned, broad-brimmed felt hat worn characteristically by travelers, and a common attribute of Hermes.
- noun Hence The winged hat or cap worn by Mercury in late artistic types.
- noun [capitalized] The typical genus of the family Petasidæ.
from the GNU version of the Collaborative International Dictionary of English.
- noun (Gr. & Rom. Antiq.) The winged cap of Mercury; also, a broad-brimmed, low-crowned hat worn by Greeks and Romans.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun historical A broad-brimmed, low-crowned
hatworn by the Ancient Greeks and Romans.
from Wiktionary, Creative Commons Attribution/Share-Alike License
He often carries a caduceus (or Herald's Staff) and wears Winged Boots/Sandles and a Winged Traveler's Hat (called a petasus).
AFP/Getty Images Brad Pitt Among the first hats distinguished by having a brim was the felt petasus or petasos of the Greeks and Romans, which tied under the chin, according to menswear historian Andy Gilchrist.
It is a statuette, apparently of gold, or, more probably, of bronze-gilt — a figure of Mercury, obviously, its head being surmounted with the petasus or winged hat, the usual accessory of that deity.
Harlequin is the god Mercury, with his short sword _herpe_, or his rod, the _caduceus_ (which has been likened to the sceptre of Judah), to render himself invisible, and to transport himself from one end of the earth to the other, and that the covering on his head, the winged cap, was the _petasus_.
Another species, the Butter bur (_Tussilago petasites_),  is named from _petasus_, an umbrella, or a broad covering for the head.
The modern hat can be traced back to the _petasus_ worn by the ancient Romans when on a journey; and hats were also thus used by the earlier Greeks.
Egina marbles, and have something of the same effect: the small round hat is in the form of Mercury's petasus; and the shoes and gaiters of the greater number are excellently adapted to defend the legs and feet in riding through the thickets.
On his head he wore a _petasus_ of hyacinthine hue, out of which sprang three peacock's feathers.
Then, gathering up her long, thick hair, she confined it close above her head, drawing down upon it the hat that lay beside the cloak -- a broad-brimmed Greek petasus, admirably adapted for concealment as well as protection.
It is a statuette, apparently of gold, or, more probably, of bronze-gilt -- a figure of Mercury, obviously, its head being surmounted with the petasus or winged hat, the usual accessory of that deity.