World War II /ˌwɜːld wɔː ˈtuː $ ˌwɜːrld wɔːr-/ BrE AmE ( also the Second World War )
(1939–1945) a war involving almost every major country in the world. On one side were the Allies (including the UK, France, and Poland, and after 1941 the US and the Soviet Union) and on the other side the Axis (including Germany, Japan, and Italy). The war was started by Adolf Hitler, the Nazi leader of Germany, who aimed to increase German power by attacking other countries and taking control of them.