to the confused person...

Here is a list of the abbreviations/nicknames used regularly as well as the fraternities/sororities with no common nickname(usually because their name is already short):

FRATERNITIES:
SAE- Sigma Alpha Epsilon
Pike- Pi Kappa Alpha
Beta- Beta Theta Pi
ATO- Alpha Tau Omega
KA- Kappa Alpha
ZBT- Zeta Beta Tau
Del- Delta Tau Delta
Kappa Sig- Kappa Sigma
TEP- Tau Epsilon Phi
Pi Kapp- Pi Kappa Phi
Phi Tau- Phi Kappa Tau
AEPi- Alpha Epsilon Phi
AGR- Alpha Gamma Rho
Pi Lamb- Pi Lambda Phi
FIJI- Phi Gamma Delta
TKE- Tau Kappa Epsilon
Phi Sig- Phi Sigma Kappa
DU- Delta Upsilon
Phi Delt- Phi Delta Theta
LXA- Lambda Chi Alpha
Theta Chi
Sigma Chi
Sigma Nu
Chi Phi
Delta Chi

SORORITIES:
ADPi- Alpha Delta Pi
AOII/AOPi- Alpha Omicron Pi
XO- Chi Omega
AEPhi- Alpha Epsilon Phi
AXO- Alpha Chi Omega
DG- Delta Gamma
Pi Phi- Pi Beta Phi
DZ- Delta Zeta
Theta- Kappa Alpha Theta
KKG- Kappa Kappa Gamma
ZTA- Zeta Tau Alpha
SK- Sigma Kappa
KD- Kappa Delta
DDD/TriDelt- Delta Delta Delta
Deeph/DPhiE- Delta Phi Epsilon
Phi Mu