A statement meant to draw an audience's attention to a point one wishes to make (which may or may not be serious in nature), often used as a segue after a joke, aside, or something that is non-relevant. I just flew in from Miami, and boy are my arms tired! But seriously, folks, how is everyone tonight? I like a good cheeseburger as much as the next guy, but seriously, folks, does anyone really need one that weighs three pounds?

To treat, consider, or approach someone or something with the seriousness or importance that it or they deserve. I wish we had taken her seriously; at the time, her claims seemed too outlandish to be true. If you don't start taking this work seriously, we're going to have to dismiss you from the company.