While it is true that there weren't any wars called World Wars before 1914, what really distinguished those wars was the weapons technology and the massive devastation that resulted from that. Human nature does not change as quickly as technology does, though, and if you define a world war as a war that involved all the major powers of the time, there were in fact four wars in Europe before that that involved all the great powers of the time in two rival alliances: the Thirty Years War, the War of the Spanish Succession, the Seven Years War of 1756-63, and the Revolutionary and Napoleonic Wars.
With that in mind, that makes world wars considerably more commonplace. Given the timing between the six world wars, we're in a definite lull. Nuclear deterrence is likely the major reason for that.