Prop keys
A second set of keys that can be left on top of a desk to give the impression that you are in the office (versus on a long lunch or having left early) but just not at your desk. An extra cell phone or --in the case of military personnel--a beret or other headgear--can to be used in a similar fashion.
Boss: "Bill, can't have gone far...his keys are on his desk."
Uncool Coworker: "That's true, unless those are prop keys."
Uncool Coworker: "That's true, unless those are prop keys."
prop key
A random set of keys to leave on your desk that will give your boss and colleagues the impression that you are in the office, just not at your desk. Helpful when taking a long lunch or cutting out of the oFfice early. Certain military members (with desk jobs) can enhance the effect by leaving the prop keys on top of an extra piece of uniform headgear (beret or other hat)
Boss: Where's Bill? Coworker: I'm not sure, but he could not have gone far since his keys are on his desk. Boss: Okay, I'll catch him later. Coworker thinks "maybe not, if those are his prop keys."