The phrase "seat of war" refers to a place where a military conflict is taking place or where important military operations are coordinated. There are many synonyms for this phrase that can be used in different contexts. "Battlefield" is a term often used to describe a place where actual battles take place. "Frontline" refers to the area where opposing armies confront each other. "Warzone" and "combat zone" are also widely used to describe areas affected by war. Another term that is often used is "theater of operations," which refers to a specific geographical area where military operations and maneuvers take place. Overall, there are many words and phrases that can be used to describe places of war, depending on the context and the specific elements of the conflict.