How many nations were involved in World War 1?
there where 6 nations involved in WW1
The Hundred Years' War involved primarily France and England, and while eventually a significant portion of Europe became involved as well, it was hardly a "world" war. I don't think any non-European nations were involved at all (and certainly no Western Hemisphere nations, because it happened before Europeans were even aware there was a Western Hemisphere).
During the course of World War II, most of the world's modernized nations became embroiled in the titanic struggle between the Allies and the Axis Powers, along with many other nations around the globe. Several large European nations that managed to avoid outright hostilities (although they were sometimes involved in non-combative roles) were Spain, Portugal, Sweden, Ireland, and Switzerland.
They were called world wars because most large military powers in the world were involved, and it affected the whole world. It also was the single biggest conflict that involved so many nations at the same time. As a matter of fact second world war was spread across continents and had the biggest human casualties ever.
World War One was significant in a negative manner. It was the first world wide war that involved many nations and many battles. Loss of lives was immense. Some 5 billion people died. It was so brutal that it was called the "war to end all wars". It did give birth to the League of Nations, designed to prevent wars, but it was ineffective. The war brought into play new weapons, and trench warfare.
World War I was so named in retrospect with reference to World War II. At the time that World War I was being fought, it was simply known as "the Great War". These two wars were termed "World Wars" because they involved so many more countries than had every been part of any previous war. In the past wars were usually fought between two factions within a nation or a couple of nations or perhaps…