The supralittoral zone is the area on the beach that gets wet sometimes when the big waves come crashing in, but most of the time it is dry. Think of it like a bathtub that sometimes gets filled up with water when you take a bath, but most of the time it is empty.
There are lots of different animals and plants that live in the supralittoral zone, some of them are really good at surviving in the salty, sandy environment. For example, there are crabs that tunnel into the sand and hide during the day and come out to feed at night. There are also special types of plants that can tolerate being blasted with salt water and sunlight all day.
If you ever go to the beach, you might be able to see the supralittoral zone if you look closely. It’s the area where the sand looks a little different, and there might be some shells or seaweed scattered around. Just be careful not to step on any animals that might be hiding in the sand!