Loli clarification

I was browsing Danbooru today and happened upon some explicit images from Gunslinger Girl today. And I don't exactly have a privileged account.

So, before I tag them "loli" and thus drop them forever out of my view, I wanted to stop by the forums and get clarification on what exactly gets that tag. Is it all girls under 18, or is it only pre-pubescent girls? (All of the Gunslinger Girls are in their mid-to-early teens.)

No breasts, no pubic hair, pre-teen proportions, and sexually explicit.

Okay, so simply knowing a char is less than 18 does not loli make.
Thanks for clearing that up.