Gil.

[Ceil]

It's gold. Probably derived from "gilt" or "gilded" (having to do with gold), but shortened to make their own groovie little word.

EDIT: And I just read that other forum, where "Giru" was mentioned. This is probably engrish for "Gilda", the term I was apparently on about (I somehow didn't know the root term), and that dude below me brought up. Or "Giru" could be japanese for "Gold". I don't speak the language.