English
hydro-geothermal
From hydro- + geothermal.
Formed from hydro- + geothermal
Proto-Indo-European *wed- ‘water’
Proto-Indo-European *wódr̥ ‘water’
Proto-Hellenic *údōr ‘water’
Ancient Greek ῡ̆̔́δωρ ‘water’
English hydro-
Today it means
adj That employs water heated geothermally
Language periods are conventional ranges, not dates for this word.
Etymograph / hydro-geothermal