War

War was a type of conflict.

The Time Lords warred with the Great Vampires during the Dark Times. (TV: State of Decay) They also engaged in two major time wars which appeared to destroy Gallifrey: the War in Heaven against the enemy, (PROSE: Alien Bodies, The Ancestor Cell) and the Last Great Time War against the Daleks. (TV: Dalek, The Day of the Doctor)

Earth had at least six world wars: Two in the 19th century, (TV: Twice Upon a Time, PROSE: Timewyrm: Exodus) two between the 20th and 25th centuries, (AUDIO: Frostfire) one in the 37th century (COMIC: Art Attack) or the 49th century (AUDIO: Singularity) and one in the year 5000 (TV: The Talons of Weng-Chiang; AUDIO: The Butcher of Brisbane) The Ninth Doctor mentioned he was present at World War V. (TV: The Unquiet Dead)

After the First Doctor helped defeat the Daleks during the First Dalek War, his granddaughter Susan stayed on Earth with resistance fighter David Campbell. (TV: The Dalek Invasion of Earth, Prelude Deceit)

The War Lords kidnapped humans from various wars in Earth's history to create an army to conquer the galaxy. (TV: The War Games)

The Rutans and Sontarans were at war with each other for thousands of years. (TV: The Time Warrior, The Sontaran Experiment, TV: Horror of Fang Rock, The Poison Sky)

Just prior to invasion of Earth by the New Dalek Empire in 2009, General Sanchez, director of UNIT's base in New York City, announced "ladies and gentlemen, we are at war!" (TV: The Stolen Earth) Similarily, in the face of an attack on the Game Station by the Daleks in the year 200,100, Jack Harkness announced "this is it, ladies and gentlemen, we're at war!" (TV: The Parting of the Ways)

Article 15 of the Shadow Proclamation said that murder was not a rule of war. (PROSE: Diamond Dogs)