At GT, we have Phi Kappa Psi, Phi Kappa Tau, Phi Kappa Theta, and Phi Kappa Sigma. The first two go by "Phi Psi" and "Phi Tau," respectively, but the latter two argue over who has more of a right to call themselves "Phi Kaps." Personally, I've always referred to Phi Kappa Theta as the "Phi Thetas," because there's no one else with whom they could be confused. You can't really shorten Phi Kappa Sigma's letters any other way without confusing them with another group (such as Phi Sigma Kappa, who we also have on campus)...plus they're older, both nationally and on our campus, so I figure they have more of a right to the term.
I'm considerably biased though, so whatever.
