World War Definition: What constitutes a 'world war'? How many countries need to be involved?
And who decides at which point a number of regional skirmishes can be grouped together and called a World War?
At the time, who called the official start of World War 1 and World War 2?
And have you noticed that although the term 'World War Three' is freely used in the alternative press and on the Internet, all the major news networks have stoically avoided using any phrase reminiscent of World War. Since it's difficult to find a definition for an event which has only happened twice in modern history, here's my attempt at an answer to the question 'what constitutes a world war'? A World War is a military conflict spanning more than 2 continents, in which at least 20 major countries participate in an attack against a common enemy, and which has the attention of the man-in-the-street due to the significant loss of life.
With that definition, we can agree that WW1 and WW2 were in fact World Wars (both wars involved some degree of participation from most of the world's then existing countries: Britain, France, Germany, Italy, Japan, the United States and the Soviet Union). We can also agree that we are very close to achieving World War 3.
Thee only requirement left to fulfill the start of WW3 is that of a military conflict spanning more than 2 continents. As soon as Israel attacks Palestine, or North Korea attacks South Korea or the US, or China invades Taiwan, we will have the next World War well underway.