Okay kiddo, imagine you have a picture of yourself and you want to see what it would look like if you looked at it in a mirror. You would see a reflection of yourself, right?
Now imagine taking that picture of yourself and sliding it along a piece of paper. You would have the original picture and a new picture that's been moved a little bit, right?
Well, a glide reflection is kind of like that! It's a type of transformation in geometry where if you take a shape or picture and you reflect it (like looking in a mirror), but then also slide it along a line at the same time, you get a new shape or picture.
So, it's like having a reflection but also moving it a little bit at the same time. Pretty cool, huh?