1. To relax or calm down; to be less energetic or intense. We have a room in our office where staff can go to just key down if they start feeling overwhelmed. It took me a long time to key down after the argument with my roommate.
2. To make something less intense. A noun or pronoun can be used between "key" and "down." The doctor prescribed me some new medication to hopefully key down my anxiety a bit. They were really excited, but I could tell they were keying it down for my sake.
3. To use a keyboard to move downward on a computer screen. Often followed by "to." After the pop-up menu appears, you'll be able to key down to the network you want to set up.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.