Foxfire is a type of glowing fungus that holds a bluish-green glow. It is mentioned once in Book 1: Keeper of the Lost Cities.
Foxfire Academy Edit
According to Alden, the name is supposed to symbolize a glowing light in the darkness. This metaphor is used to refer to the school prodigies as the light. Sophie ridicules the name in the first book by remarking about how the Elvin world's most prestigious academy was named after a type of fungus and keeps on insisting that foxfire is still just a glowing fungus, causing Fitz to feel a bit insulted.