n.
1.a war between the allies (Russia, France, British Empire, Italy, United States, Japan, Rumania, Serbia, Belgium, Greece, Portugal, Montenegro) and the central powers (Germany, Austria-Hungary, Turkey, Bulgaria) from 1914 to 1918
Idiom of the Day
over (someone's) head
beyond one's ability to understand something
The joke went over the girl's head and she did not understand it.