Lithosphere
Pronunciation : Lith"o*sphere, n. [Litho- + sphere.] (Phys. Geog.) (a) The solid earth as distinguished from its fluid envelopes, the hydrosphere and atmosphere. (b) The outer part of the solid earth, the portion undergoing change through the gradual transfer of materia
Part of Speech : regarded
Definition :
as a third mobile envelope comparable with the hydrosphere and atmosphere.
Source : Webster's Unabridged Dictionary, 1913