The collective nickname for three major fraternities founded at Miami University; Beta Theta Pi, Phi Delta Theta, and Sigma Chi. Phi Kappa Tau was founded at Miami also, but for whatever reason isn't included in this collective nickname.
At some schools the three fraternities usualy come together (and pretend that they like each other)to have one major social every year.
The "Miami Triad" social this weekend will be a TOTAL sausage fest. At least it usually attracts some sexy soro-chics like the Chi Os, Gamma Phis and DZs.