1. adjective Calm and stable. I know this is a stressful time, but we need to try keep things as even keel as possible.

2. noun A calm and stable situation. The phrase alludes to a ship's keel, a supporting structure that helps to keep the ship stable in the water (and thus needs to be "even" or level). Whoa, let's all stop yelling and try to get back on an even keel!