Zettai ryōiki is a Japanese term that means "absolute territory." It refers to the area of skin that is visible between the top of a girl's socks or stockings and the bottom of her skirt or shorts. It's kind of like when you wear boots and shorts - you can see your legs and a little bit of skin between your socks and shorts, right? That's what zettai ryōiki is all about.
Some people think that zettai ryōiki is cute or sexy. They like the way it looks when a girl shows a little bit of skin in that area. In fact, some anime and manga characters wear clothing specifically designed to show off their zettai ryōiki.
However, it's important to remember that everyone has different opinions about what is cute or sexy, and what is appropriate to wear in different situations. It's always a good idea to dress in a way that makes you feel comfortable and confident, and to make sure you're following any dress codes or rules that are in place at school or other places you go.