Definition - What does Crust mean?
Crust describes an external coating or covering. In geology, it is the term given to the outermost layer of our planet earth or that of any other planet. The earth's crust is composed of a large variety of all three types of rock: igneous, metamorphic and sedimentary. Beneath the crust lies the earth's mantle.
Safeopedia explains Crust
The earth's continental crust is very important, as it is the most stable part of the earth. If there were no crust we would have to live on the earth's mantle, which is very hard and very hot and, thus, not suitable for the survival of our species. The earth's crust is more malleable or easier to break apart and provides raw materials and nutrients for plant life that feed all species.