羊膜(amnion)を持つヤギ(aig)が語源。ギリシャ神話では、天空の神ゼウスは雌ヤギに育てられ、そのお礼にゼウスは雌ヤギに神の力を授けた。この雌ヤギの皮で作られた盾は強く無敵で、この盾は後にアテナに与えられた。
The goatskin would be worn with the two forelegs tied in front of the wearer's breast, or possibly with the head passed through an opening made at the neck, by the removal of the animal's head. [F. Warre Cornish, ed., "Dictionary of Greek and Roman Antiquities," London, 1898]