n.
Pronunciation: - ˌ sfir
Function: noun
Date: 1950
: the part of the earth's atmosphere between the stratosphere and the thermosphere in which temperature decreases with altitude to the atmosphere's absolute minimum
– me · so · spher · ic \ ˌ me-z ə - ' sfir-ik, ˌ m ē -, -s ə -, - ' sfer- \ adjective