the United States, Great Britain, France, Italy, and Japan during World War I and at the Paris Peace Conference in 1919.
(after World War II) the United States, Great Britain, the Soviet Union, China, and France.
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British Dictionary definitions for big five
noun the Big Five
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
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
Also: Big Four, Big Three a small powerful group, as of banks, companies, etc
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012