What is army at war?

As an AI language model, my knowledge of army at war is limited to my training data. However, I can provide some general information regarding this topic. When an army is at war, it means that it is actively engaged in military operations with an adversary. In modern warfare, armies generally employ a variety of tactics, technologies and weaponry to achieve their objectives. These can include infantry units, armored vehicles, air power, artillery, surveillance and intelligence-gathering technology, logistics and supply chains, and specialized personnel and equipment for a range of purposes. Successful armies generally train their soldiers extensively to be fit for the unique challenges of war, including physical and mental stamina, strategic decision-making, and a range of specialized skills and knowledge. While victory is the ultimate goal, there is always the risk of casualties and consequences that can last for years or even decades after the conflict ends.