n.
Pronunciation: as- ' the-n ə - ˌ sfir
Function: noun
Etymology: Greek asthen ē s weak + English -o- + sphere
Date: 1914
: a zone of a celestial body (as the earth) which lies beneath the lithosphere and within which the material is believed to yield readily to persistent stresses
– as · theno · spher · ic \ - ˌ the-n ə - ' sfir-ik, - ' sfer- \ adjective