We consider a war to be a military conflict in which at a minimum, for each side in the conflict, there is or was an actual risk that it could lose—that it would not attain its objectives—that there exists or existed a real possibility that it would not achieve the goals for which it entered into the conflict.
In addition to this minimum requirement, among other criteria that we might validly take into the consideration of whether a military conflict is or was a real war, would be how great the cost to both sides is or was.