The outer layer of the Earth is called the crust. Let's understand this in simple terms:
The Earth is made up of several layers. Imagine the Earth like an onion with different layers, with each layer varying in composition and physical properties. The outermost of these layers is the crust.
The crust is similar to a thin shell around the Earth. It is very thin compared to the other layers and can be thought of as the Earth's skin. It is made up of solid rocks and minerals and is where we live and see landscapes, mountains, and oceans.
Below the crust is the mantle, which is much thicker and composed primarily of semi-solid rock. Therefore, when talking about the outermost layer, we refer specifically to the Earth's crust.