The latter 'GP'-based explanation (from the term "general purpose"), though this does appear in the "TM9-803 Manual" (page 10), and the car is designated a "GP" in the "TM9-2800 Manual" — these were published in late 1943 and early 1944, and their influence on the jeep's name is dubious. One reason being: the jeep wasn't the only of the Quartermaster Corps' "general purpose" vehicles – so if this was the source, people would have nicknamed others "geeps" or "jeeps" as well, as they did before.<br> More influential perhaps, was the 1943 short propaganda / documentary film "The Autobiography of a 'Jeep, by the U.S. Office of War Information, in which the jeep itself literally propagates this origin story of its nickname.