What is the term for the center of the Earth?

The center of the Earth is referred to as the core. The core consists of two parts: the outer core, which is liquid and composed mainly of iron and nickel, and the inner core, which is solid due to the immense pressure. This designation is based on seismic studies and our understanding of Earth's internal structure, which identifies distinct layers based on their composition and physical state.

The crust refers to the outermost layer of the Earth where we live, while the mantle lies beneath the crust and is composed of semi-solid rock that flows slowly over time. The term "outer layer" is not a scientific designation used in geology and does not specify any of the known layers of the Earth’s interior. Understanding the organization of the Earth into these layers, with the core at the center, is vital for grasping geological processes such as tectonic activity and heat transfer from the interior to the surface.