By April 1942 newspaper editors weren’t sure what to call the new fangled quarter-ton bantam-willys-ford invention. The problem was highlighted in this Sarasota-Herald-Tribune article which surveyed editors’ uses of different descriptive words. Note the naval editor’s response at the very bottom of the article.

Eventually, a decision was made. In May of 1942 newspapers announced the armored division officially named the quarter-ton command/reconnaissance car the ‘Peep’, while the half-ton armored car was called the ‘Jeep’. The Milwaukee Journal published two photos to help readers distinguish between the two.

That’s a Ford GP at the top, while at the bottom is what I believe to be an early Dodge Command Car. You can view other earlier examples like the one above at the Command Car site.

This article in the Pittsburgh Press, in May of 1942 confirms that the names “jeep” and “peep” had been transformed from slang into legitimate words that could appear in dictionaries.

As late as 1984, some WWII vets didn’t know why they called the jeep a peep. According to this article in the Spokane-Review, Patton’s 3rd Army Armored Division continued to call the jeep a peep throughout the war.