Gaia
noun
ˈgī-ə 
: the hypothesis that the living and nonliving components of earth function as a single system in such a way that the living component regulates and maintains conditions (such as the temperature of the ocean or composition of the atmosphere) so as to be suitable for life
also : this system regarded as a single organism
Word History
Etymology
after Greek Gaîa, a primordial earth goddess in Greek myth, literally, "earth" — more at geo-
First Known Use
1972, in the meaning defined above