What does hydro mean?
Hydro is an informal word for hydroelectricity: electricity produced by harnessing the movement of falling or flowing water. It is commonly used in discussions of energy systems, especially in regions where dams and water-driven generating stations supply a substantial share of the electricity grid. The term can also refer informally to a hydroelectric power station itself, although hydroelectric power station is more precise and more formal. “Hydro” is often contrasted with generation from coal, oil, natural gas, nuclear power, or renewable sources such as wind and solar power. In everyday use, it conveys both the source of the electricity and, by extension, the facility that produces it. The abbreviated noun comes from “hydroelectric,” while the underlying element hydro- comes from Greek hýdōr, meaning “water,” the same root found in words such as hydrogen, hydraulic, and hydration.
nounElectricity generated by the movement of water, especially in a hydroelectric power station. It is also used informally to refer to such a power station.
- Electricity generated by flowing or falling water.
- Informally, a hydroelectric power station or facility.
"Much of the region's electricity comes from hydro rather than fossil-fuel plants."
"The dam supplies hydro to communities along the river."
"During the drought, the country relied less on hydro and used more gas-fired generation."
The noun is normally used as an uncountable mass noun, especially when referring to electricity generated from water.
"The grid operator increased the amount of hydro available during the wet season."
Hydro is where the ancient Greek root for water meets modern electrical power.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does hydro come from?
The standalone noun is an informal shortening of hydroelectric, while its initial element comes from the combining form hydro-, meaning “water” or “power derived from water.” That combining form derives from Greek hýdōr, “water.” The Greek root also underlies related English words including hydrogen, hydraulic, hydrant, and hydrate.
How hydro is actually used
The word is informal and abbreviated; hydroelectricity or hydroelectric power is the more formal term. When referring specifically to the facility rather than the electricity it produces, hydroelectric power station is usually clearer.
Easily confused with hydro
Hydro means electricity generated by moving water, whereas hydrogen is a chemical element and a gas that can be used as an energy source.