Search Result for "asthenosphere": 
Wordnet 3.0

NOUN (1)

1. the lower layer of the crust; 



The Collaborative International Dictionary of English v.0.48:

asthenosphere \asthenosphere\ n.
   1. the lower layer of the earth's crust, below the
      lithosphere. It is estimated as from fifty to several
      hundred miles thick. It is less rigid than the
      lithosphere, but still rigid enough to transmit some
      transverse seismic waves. --[RHUD]
      [WordNet 1.5 +PJC]


WordNet (r) 3.0 (2006):

asthenosphere
    n 1: the lower layer of the crust