A catslide roof is a type of roof that looks like a big triangle. It might be easier to think of it like a slide for cats to climb up and down on!
Imagine a house with a regular roof – it slopes downwards on both sides. Now, imagine that one of the sides was longer than the other. That longer side would be the catslide! It's called a catslide because it looks like a cat trying to climb up something steep.
Catslide roofs were often used on old houses in England and parts of Europe. They were popular because they allowed for more living space in the attic or upper floors of the house. The longer side of the roof would come down close to the ground, which meant that the upper floors could be taller and more spacious.
So, if you see a house with a really big triangle-shaped roof that looks like a cat could climb up it, it's probably a catslide roof!