A loop is like a never-ending staircase. You start at the top, take a step, and before you know it, you've been here all along.
Or, in programming terms, a loop is a way to repeat a set of actions over and over until you get tired of it. Kind of like this website.
You can find more information on loop types, or if you're feeling adventurous, try loop games!
But be warned, loops are not just for programmers. They can also be found in nature, like the loop of a rollercoaster or the loop of a jump rope. Just don't try to loop the loop of your responsibilities.