What is the solid crust of the earth known as?

The solid crust of the Earth is known as the lithosphere. This term specifically refers to the rigid outer layer of the Earth that includes the crust and the uppermost part of the mantle. The lithosphere is characterized by its solid, rock-like nature, which supports life, landforms, and various ecosystems. It encompasses the continents and the ocean floors and plays a critical role in various geological processes, such as tectonics and volcanism.

The other terms provided refer to different components of the Earth. The hydrosphere encompasses all water found on Earth, including oceans, rivers, lakes, and water vapor. The atmosphere is the layer of gases surrounding the planet, vital for weather and climate. The geosphere refers broadly to the entire solid part of the Earth, including the lithosphere, but the specific term for the solid crust is lithosphere. Thus, the most accurate and precise term for the Earth's solid crust is indeed lithosphere.