How was Wold War 1 a world or global war?
The countries involved had colonies all over the world, and they were at war too.
To differentiate it from the Second World War. World War I (WWI) was a global war centered in Europe that began in 1914 and lasted until 1918. It was predominantly called the World War or the Great War from its occurrence until the start of World War II in 1939, and the First World War or World War I thereafter.
The war that was fought from 1914-1919 was called the Great War or the World War during and after the fighting. It was a global, i.e. worldwide, military conflict that involved most of the world's great powers and many lesser powers. It was not called World War 1 until the wars that began in 1939 in Europe and earlier in Asia came to be seen as a single global conflict. Then the two had to…
Well, World War One and World War Two have both been called "The Great War." This is posted in the WW2 section, so I'll answer this as if you were referring to it. Germany declared war on Poland, technically starting the war. Britain and France were allied with Poland, so they declared war on Germany, and the rest is history.