arboretum
1. A place where everybody belongs to a clique (because everyone has labels, like the plants in an arboretum). Sometimes shortened to arb.
2. Used to describe when simple-minded people n00bs move online acronyms over into real life, labelling their emotions with acronyms.
1. "Mike's not a jock, he's not a bad guy, this ain't an arboretum"

2.'Tard: "Ell Oh Ell"
Me:"Hey Dipshit, this is not a fucking arboretum." 