The part of the earth’s interior lying above the outer core and below the Mohorovicic discontinuity. The mantle is commonly divided into three parts: the upper mantle (depths down to ~400 km), the transition zone (~400-670 km depth), and the lower mantle (~670-2900 km depth).
Glossary of Volcanic Terms - G. J. Hudak, University of Wisconsin Oshkosh, 2001