High Quality Content by WIKIPEDIA articles! Fraternities and sororities (from the Latin words frater and soror, meaning "brother" and "sister" respectively) are fraternal social organizations for undergraduate students. In Latin, the term refers mainly to such organizations at colleges and universities in the United States, although it is also applied to analogous European groups also known as corporations. Similar, but less common, organizations also exist for secondary school students. In modern usage, the term "Greek letter organization" is often synonymous, in North America, with the terms "fraternity" and "sorority".