Aegis is Athena's shield. In the Japanese version, there's no differentiation between her name and the name of the shield. The Japanese pronunciation for the same word- aegis- differs from English though... eye-gis instead of ee-jis. The pronunciation was basically kept, and the spelling was changed to reflect it. Tomato(to-may-to), tomato(to-mah-to), she's named after the shield.
crunchy612 posted... ^that, basically. Not too hard if you're into Greek myths - i figured it out when i found out Aigi initial persona is Palladion, named after some important statue of Athena in Troy. Iirc. >_<
Yup. http://en.wikipedia.org/wiki/Palladion. It's why Athena is sometimes called Pallas Athena. As I understand it her persona is basically going from an icon to the the actual goddess.
Also, from the MegaTen wiki: "The spelling Aegis as appears in the original Japanese region titles is technically a misspelling of [Japanese text]; in English. The correct spelling Aigis is acceptable and a technically superior rendering of the original Greek. In fact Aigis is the preferred spelling of the proper noun by contemporary academic standards." (http://megamitensei.wikia.com/wiki/Aigis)
Aegis is a word that she's obviously connected with. Aigis is, while likely more faithful, a far rarer, basically technical spelling. Since there's no difference in the Japanese name from the shield, it's basically inevitable that some of the released and media information would spell it as Aegis. And I'm sure some people just decided that she's named after the shield and the spelling change was just to make her more robotic or exotic or whatever. In the end, it's three different languages with three different writing systems and three different pronunciations... no matter how you do it, something will be lost in translation.