lithosphere

This term describes the brittle, outermost shell of the planet, encompassing both the crust and the uppermost portion of the mantle. It is characterized by its rigidity, which allows it to break into distinct tectonic plates that slide or collide. As a scientific term, it is treated as an uncountable mass in most geological contexts, referring to the global layer rather than individual segments. It is distinct from the biosphere or atmosphere in that it defines the solid, mineral-based foundation of the Earth.