Final answer:
The rigid outermost layer of Earth is called the crust, which is part of the lithosphere and is distinct from the deeper mantle and core layers.
Step-by-step explanation:
The rigid outermost layer of Earth is called the crust. Earth's crust is a thin, brittle outer shell made of rock. It varies from the rest of the interior by composition and physical properties, being less dense and cooler than the layers beneath it. There are two types of crust, continental and oceanic, characterized by different compositions and thicknesses. The crust is part of the larger lithosphere, which also includes the uppermost part of the mantle and behaves as a rigid, brittle solid. Below the crust is the mantle, which extends down to a depth of approximately 2900 kilometers and consists of solid rock that can deform and flow slowly under high temperature and pressure conditions. The Earth's core is divided into the inner and outer core, with the outer being liquid and responsible for generating Earth's magnetic field, and the inner core being a solid composed of iron and nickel alloy.