Hydr (water)
Hydr
Greek hydor: water.
Firefighters connected their hose to a hydrant.
Hydroelectric
Making electricity from the power of moving water.
A hydroelectric dam supplies power to towns in Himachal.
Hydrogen
A light gas; joined with oxygen it makes water.
Water is made of hydrogen and oxygen.
Remember: Hydrogen = 'water-maker', because it forms water when it burns. Hydr is Greek water; aqua is Latin water. Stay hydrated = drink enough water.