Help Me Understand – What does “Bet” mean?

I’m a big fan of words. I love writing, I love reading, but there are some words I’ve heard recently that I don’t understand. They’re words being spoken by the next generation … and there are either new words or new meanings! And I’m struggling to keep up. Lucky for me, I’ve got some experts at home: two teen sons and a pre-teen daughter. I decided to put my 15-year-old son Austin on the spot first, and I’m asking Austin to Help Me Understand, “What does the word ‘bet’ mean?”