<P> The term `` First World War '' was first used in September 1914 by the German biologist and philosopher Ernst Haeckel , who claimed that `` there is no doubt that the course and character of the feared ' European War ' ... will become the first world war in the full sense of the word , '' citing a wire service report in The Indianapolis Star on 20 September 1914 . After the onset of the Second World War in 1939 , the terms World War I or the First World War became standard , with British and Canadian historians favouring the First World War , and Americans World War I . </P>
when was the first world war called that
September 1914 by the German biologist and philosopher Ernst Haeckel