Allied Powers
Now we are into the war itself. Instead of referring to the two sides as the Triple Alliance and Triple Entente, we use Central Powers and Allied Powers. This is especially important since there are some key differences. For one, there are more than three Allied and Central Power nations. With the Allied Powers there is also the United States starting in 1917. Also, Japan fights for the Allies in China against German-occupied lands. Italy also switches sides in 1915. Italy, being involved in the Triple Alliance as well as a secret deal with France, ends up siding with France after promises of new land.