User blog comment:Lex wa Kaiho/What is Lumen Histoire?/@comment-5551986-20130510093140

I think its an actual fairy, they say Zeref bought magic to the world or something right? Maybe its Zeref's opposites like Yin-Yang or something stupid like that.

Judging by its name, Lumen (measurement of light by the amount of flux or something stupid i cant be bothered to explain) Histoire (history) it could mean the history of light, although vaguely.

BUT a lumen can also mean the central cavity of a hollow and tubular organism or cell. Which I doubt it would be interpreted as such, so it would mean: History of the organisms cavity?

If its not a fairy I think it has something to do with the magic that exists in the world perhaps.