Definition:
"World War 1" is a noun that refers to a major conflict that took place from 1914 to 1918. It was fought between two main groups: the Allies (which included countries like Russia, France, the British Empire, Italy, the United States, Japan, Romania, Serbia, Belgium, Greece, Portugal, and Montenegro) and the Central Powers (which included Germany, Austria-Hungary, Turkey, and Bulgaria).
World War 1 was a significant event in history that involved many nations and had a profound impact on the world.