Scene: We're all lying around on the floor, watching some random science channel show and the announcer says something to the effect of, "Exactly how much is not known, but a good ballpark figure is..."

The Dormouse: "Ballpark figure! It's when you don't know exactly how much something is and you just take a guess."

Me: "That's right."

The Dormouse: "And it also gets someone off your back when they're bugging you. Sometimes."