Okay kiddo, you know how a point is when two lines or edges meet, right? A quadripoint is kind of like that, but instead of just two lines or edges coming together, there are four!
Imagine that you're standing right in the middle of a big square. Each corner of the square is where two edges meet, but where all four corners meet is a quadripoint. It's a special spot where four boundaries come together at the same time.
Now, imagine that the square is actually four countries that are next to each other. Maybe they're talking about where their borders should be, and they realize that in one spot, all four borders meet. That's a quadripoint too! Sometimes people might put a marker or a monument at a quadripoint to show where it is.
Does that make sense, little one? A quadripoint is just a special spot where four lines or borders all come together at once.