1. To sit down and stop moving. Often used as an imperative. We've been hiking for a while now. Why don't we park it and have a bit to eat, shall we? I want you to park it in this chair and sit still until I'm done!

2. To stop arguing about the matter at hand; to leave some issue alone. Often used as an imperative. OK, guys, that's enough arguing. Let's just park it for a while, all right? Tommy, Sarah, park it! I've had enough of your bickering.