When we say something is thick, it’s like when you have a big, fluffy blanket that keeps you really warm. The blanket is not thin like a sheet; it’s thick and cozy, which means it has a lot of material. If you were to stack a lot of pieces of paper, it would become a thick stack, because there are many layers.
Think about a book. A thick book has lots of pages to read, while a thin book has only a few pages. When you have a thick slice of bread, it’s bigger and fluffier than a thin slice.
Imagine a forest. A thick forest has lots and lots of trees standing close together, making it hard to see through. You can also think of a milkshake. A thick milkshake is hard to suck up through a straw because it is very creamy and full of yummy stuff.
In simple words, thick means there is a lot of something packed together, making it big, full, or hard to see through or get through.