501(c)(7)
The US tax-exempt classification for social and recreational clubs, which many fraternities and sororities fall under.
501(c)(7) is the section of the US tax code covering nonprofit social clubs, the category most social fraternities and sororities use. It generally exempts member dues from federal income tax but limits how much income can come from nonmembers. Chapters should confirm their status and filing requirements with their nationals or an accountant, as rules vary.