A jeep was an automobile designed on Earth in the mid-twentieth century. It was used for travel off of paved roads. Jeeps were used by the military for transport over rough terrain.
Ace put Kathleen and Audrey Dudman into a jeep in 1943 to get them away from the Haemovores. She told them to go to London, where Ace's nan would look after them. (TV: The Curse of Fenric)
In 2009, ATMOS was so popular it was installed in most UNIT jeeps. (TV: The Sontaran Stratagem / The Poison Sky)