Interplanetary war

An interplanetary war was a war fought between planets, examples including the Human-Draconian War, the Second Dalek War, and the Third Dalek War. (PROSE: The Chase)

By the time he first battled the Third Doctor, the Master was already responsible for several Interplanetary Wars. (PROSE: Doctor Who and the Terror of the Autons)

In 2006, Earth's first interplanetary war was anticipated as the British government requested that the United Nations provide access codes for nuclear weapons against an alien threat. In reality, this was a Slitheen plot to destroy the Earth for profit, which was thwarted by the Ninth Doctor. (TV: World War Three)

Over the 50 years following sending a rocket to Mechanus, Earth became involved in interplanetary wars which put an end to Earth's expansionist phase, leaving planets like Mechanus uncolonised. (PROSE: The Chase)