n 1. (Government, Politics & Diplomacy) the five countries considered to be the major world powers. In the period immediately following World War II, the US, Britain, the Soviet Union, China, and France were regarded as the Big Five
2. the lion, the elephant, the rhinoceros, the buffalo, and the leopard: considered to be the five principal African wild animals, esp as sought by those on safari
3. (Commerce) Also: Big Four or Big Three a small powerful group, as of banks, companies, etc