A term designating the three major U.S. automakers. Also, a 3-on-3 basketball league founded by actor and rapper Ice Cube.
The business Big Three consists of Ford, General Motors, and Chrysler. All three are headquartered in the Detroit metro area, though Chrysler was bought by Italian automaker Fiat in 2009 after the aftermath of the financial crisis of 2007-2008 forced it into bankruptcy.
There are big three automakers in other countries as well. In Japan, there's Toyota, Honda, and Nissan. In Germany, there's Volkswagen, BMW, and Mercedes-Benz. (Chrysler, who apparently loves European romances, was once part of the same company as Mercedes-Benz as well. The companies merged in 1998, but Chrysler was eventually sold to a private equity firm in 2007.)