party ball n. a five-gallon container of beer, one-third the size of a keg (in the U.S.). Editorial Note: According to numerous articles in the Washington Post, Party Ball was also the now outdated product name for “a lightweight plastic sphere that totes six large plates, small cups, dessert plates and bowls and a single serving tray. Each half of the outside shell doubles as a serving bowl.” It seems to have been primarily sold at the department store chain Hecht’s. (source: Double-Tongued Dictionary)