The term GREEK GRP. is an acronym for Greek Group, which is a term used to refer to fraternities and sororities. Fraternities, or 'frats' for short, are social organizations that are typically found on college campuses. They are usually composed of male students who share common interests and values. Sororities are similar to fraternities, but they are composed of female students. Both fraternities and sororities often have rituals and traditions that members must follow.