There are many explanations of the origin of the word "jeep," all of which have proven difficult to verify. The most widely held theory is that the military designation of GP begat the term "Jeep" and holds that the vehicle bore the designation "GP" (for "Government Purposes" or "General Purpose"), which was phonetically slurred into the word jeep.Mail Call, However, an alternate view launched by R. Lee Ermey, on his television series disputes this, saying that the vehicle was designed for specific duties, and was never referred to as "General Purpose" and it is highly unlikely that the average jeep-driving GI would have been familiar with this designation. The Ford GPW abbreviation actually meant (G for government use, P to designate its 80-inch (2,000 mm) wheelbase and W to indicate its Willys-Overland designed engine).

Many, including Ermey, suggest that soldiers at the time were so impressed with the new vehicles that they informally named it after Eugene the Jeep, a character in the Popeye cartoons created by E. C. Segar. Eugene the Jeep was Popeye's "jungle pet" and was "small, able to move between dimensions and could solve seemingly impossible problems."

Words of the Fighting Forces by Clinton A. Sanders, a dictionary of military slang, published in 1942, in the library at The Pentagon gives this definition:

Jeep: A four-wheel drive vehicle of one-half- to one-and-one-half-ton capacity for reconnaissance or other army duty. A term applied to the bantam-cars, and occasionally to other motor vehicles (U.S.A.) in the Air Corps, the Link Trainer; in the armored forces, the ½-ton command vehicle. Also referred to as "any small plane, helicopter, or gadget."

This definition is supported by the use of the term "jeep carrier" to refer to the Navy's small escort carriers.

Early in 1941, Willys-Overland demonstrated the vehicle's off-road capability by having it drive up the steps of the United States Capitol, driven by Willys test driver Irving "Red" Haussman, who had recently heard soldiers at Fort Holabird calling it a "jeep." When asked by syndicated columnist Katherine Hillyer for the Washington Daily News (or by a bystander, according to another account) what it was called, Irving answered, "It's a jeep."

Katherine Hillyer's article was published nationally on February 20, 1941, and included a picture of the vehicle with the caption:

LAWMAKERS TAKE A RIDE- With Senator Meade, of New York, at the wheel, and Representative Thomas, of New Jersey, sitting beside him, one of the Army's new scout cars, known as "jeeps" or "quads", climbs up the Capitol steps in a demonstration yesterday. Soldiers in the rear seat for gunners were unperturbed.

This exposure caused all other jeep references to fade, leaving the 4x4 with the name. The term was also in military slang use to mean vehicles that were untried, or untested.

Trade name

The original trademark brand name application was filled in February 1943 by Willys-Overland.It is also used as a generic term with a lowercase (jeep) for vehicles inspired by the Jeep that are suitable for use on rough terrain.

As the only company that continually produced Jeep vehicles after the war, in June 1950 Willys-Overland was granted the privilege of owning the name "Jeep" as a registered trademark.

Off-road abilities

This section requires expansion.

Jeep Wrangler off-roading

Jeep advertising has always emphasized the vehicle's off-road capabilities. Today, the Wrangler is one of the few remaining four wheel drive vehicles with solid front and rear axles. These axles are known for their durability and strength. Most Wranglers come with a Dana 35 rear differential and a Dana 30 front differential (44 in the case of the Rubicon). The upgraded Rubicon model of the JK Wrangler is equipped with electronically activated locking differentials, Dana 44 axles front and rear with 4.10 gears, a 4:1 transfer case, electronic sway bar disconnect and heavy duty suspension.

Another benefit of solid axle vehicles is they tend to be easier and cheaper to "lift" with after market suspension systems. This increases the distance between the axle and chassis of the vehicle. By increasing this distance, larger tires can be installed, which will increase the ground clearance, allowing it to traverse even larger and more difficult obstacles. In addition to higher ground clearance many owners aim to increase suspension articulation or "flex" to give their Jeeps greatly improved off-road capabilities. Good suspension articulation keeps all four wheels in contact with the ground and maintains traction.

Useful features of the smaller Jeeps are their short wheelbases, narrow frames, and ample approach, breakover, and departure angles, allowing them to fit into places where full-size four wheel drives have difficulty.