The word back can mean different things, kind of like how your favorite toy can be both a car and a robot. One way to think about back is like a boomerang. When you throw a boomerang, it goes far away but then it comes right back to you. So, when someone says they’ll be back, it means they will go away for a little while but then come back to where they started.
Another way to think about back is like a backpack. When you wear a backpack, it sits on the part of your body called your back. It’s the side of your body that you can’t see without a mirror, like when you play hide and seek and someone hides behind you. Your back is like a secret place that you carry with you everywhere!
Back can also be about time travel. Imagine watching a movie and you want to see a fun part again. You press the back button to go back in time and watch it again. It’s like having a magic remote control that lets you see things from the past.