ampyx

from The Century Dictionary.

• noun In Greek antiquity: A general term for a band or fillet or other female head-dress worn encircling the head, particularly when made of metal, or bearing in front an ornament of metal. A head-band for horses; also, an ornamental plate of metal covering the front of a horse's head.
• noun [NL.] A species of trilobite or fossil crustacean, found chiefly in Lower Silurian strata.
• noun In the anatomic structure of the Devonian fish Palæospondylus, an element of the anterior part of the skull.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Greek Antiq.) A woman's headband (sometimes of metal), for binding the front hair.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A woman's headband (sometimes of metal), for binding the front hair in Ancient Greece.