A hyperboloid structure is like a giant playground dome made up of many little connected circles. It's kind of like a bubble made of thousands of smaller bubbles, but instead of being round, it's more like a long, skinny shape.
These shapes are really strong and sturdy, so they're often used to build things like big sports arenas or outdoor concert stages. They're also cool to look at because they have a lot of lines and curves that all work together to make an interesting shape.
Imagine if you blew up a bunch of balloons and tied them all together in different ways - that's kind of what a hyperboloid structure is like, but on a much bigger scale!