The empirical definition of war is something like this: War is when a lot of people kill each other.
Traditionally, the definition would be more like this: War is when a lot of people kill each other in armed conflicts between two or more states.
Unconventionally, by taking the concept of 'unrestricted warfare' and expanding upon it, we could say: War is a major and integral aspect of life as we perceive it.
War is a concept which sprung from the concept of 'conflict'. (Which in turn was born from the concepts of 'duality' and 'friction'.)
Traditionally, the concept of 'destruction' was most closely tied to 'war'.
As our ability to destroy has moved beyond any possible use in warfare (with nuclear weapons), 'war' once again moves closer to the concept it was created from: 'conflict'.
Another aspect emerged and took the dominant position previously held by 'destruction': the concept of 'control'.
As the idea of war is still quite much
in flux, for now, let's say define war the following way: War is a conflict large-scale enough to swallow its context.
What can we gain from the study of war?
Well, with some study, we can learn to 'win' wars. With some more study, we can learn to 'solve' wars.
The first step of solving wars is to see them. The final step of solving wars is to see them with complete transparence.