We don’t know who started it, but every branch of the military has its own world where they created terms and slang only they could understand. Some of them could be far from their actual meaning, while others are just plain hilarious. Here is some of the slang unique to the Air Force:

Rainbow Flights

Before fresh trainees could get their official issued uniform in boot camp, they’d be walking around wearing their civilian clothes. Thus they looked like a rainbow while in formation.

Pull Chocks and Blocks

Crew members of the 436th Military Airlift Wing, dressed in chemical warfare gear, pull chocks into position during a chemical warfare defense equipment test.

Wedges are used to prevent stationary airplanes from moving. Pull chocks refer to pulling these wedges, which also means you’re about to leave the base. In short, the “Let’s go!” signal.

Prime Beef

Not used for ribeye steak. Refers to the Prime Base Engineer Emergency Force, a rapidly deployable, specialized civil engineer unit of the US Air Force with a full range of engineering support.