Definition: The Heraia was a classical Greek athletic festival for women at Olympia, at which women competed wearing a costume like the one associated in fiction with the Amazons -- the breast exposing garment.
The athletic costume or running dress for the Heraia was a short chiton, falling above the knees, pinned or knotted on the left shoulder, with the right shoulder and breast bared, which appears to have been inspired by a male athletic garment.
The Heraia may have been a prenuptial initiation rite for women, according to Nancy Serwint in "The Female Athletic Costume at the Heraia and Prenuptial Initiation Rites," American Journal of Archaeology 1993 (pp. 403-422). Pausanias refers to the costume and the game, held every fourth year and consisting of foot races, and possibly instituted in the 7th century B.C. The costume appears in Greek art by 560 B.C.
Alternate Spellings: Heraea
Examples:
Pausanias 5.16.4:[4] The games of the maidens too are traced back to ancient times; they say that, out of gratitude to Hera for her marriage with Pelops, Hippodameia assembled the Sixteen Women, and with them inaugurated the Heraea. They relate too that a victory was won by Chloris, the only surviving daughter of the house of Amphion, though with her they say survived one of her brothers. As to the children of Niobe, what I myself chanced to learn about them I have set forth in my account of Argos.