hydro
noun
hydroelectric power.
hydro
1 American
[hahy-droh]
/ ˈhaɪ droʊ /
noun
-
hydros
plural
-
Informal. hydroelectric power.
-
Informal. hydroplane.
-
British.
-
a bathhouse, hotel, or resort catering to people taking mineral-water health cures; spa.
-
an establishment furnishing hydrotherapy.
-
adjective
hydro-
2
American
hydro-
3
American
hydro
1
British
/ ˈhaɪdrəʊ /
adjective
noun
hydro
2
British
/ ˈhaɪdrəʊ /
noun
Hydro
3
British
/ ˈhaɪdrəʊ /
noun
hydro-
4
British
combining form
-
indicating or denoting water, liquid, or fluid
hydrolysis
hydrodynamics
-
indicating the presence of hydrogen in a chemical compound
hydrochloric acid
-
indicating a hydroid
hydrozoan
hydro–
Scientific
Usage
What does hydro- mean? Hydro- is a combining form used like a prefix that has two distinct senses. The first of these senses is “water,” and this form of hydro- is often used in a variety of scientific and technical terms. Hydro- comes from Greek hýdōr, meaning “water.”The second of these senses is “hydrogen,” and this form of hydro- is occasionally used in a variety of scientific terms, especially in chemistry. Hydrogen, the lightest of the elements, combines with oxygen to form water. The word hydrogen comes from French hydrogène. The suffix -gen, or its equivalent in French, means "that which produces." Hydrogen literally translates to "that which produces water."What are variants of hydro-?When combined with words or word elements that begin with a vowel, hydro- becomes hydr-, as in hydrant. Want to know more? Read our Words That Use article on hydr-.
Other Word Forms
Noun Inflected Forms
Etymology
Origin of hydro1
1880–85; by shortening of compounds with hydro- 1 ( cf. -o); hydro ( def. 4 ) hydro- 1 analyzed as an adj.
Origin of hydro-2
< Greek, combining form of hýdōr water
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Massachusetts requires roughly 69% of electricity supply to come from qualifying renewable or clean-energy sources like Canadian hydro.
From MarketWatch ● Sep. 10, 2026
He thought solar, wind and hydro power would each present their own environmental problems.
From Salon ● Jun. 26, 2026
“I will advance renewable energy, import less foreign fuel and stop decommissioning of hydro and nuclear power. However, many current initiatives have unintended consequences, and my plan focuses on incentives, not mandates,” she said.
From Los Angeles Times ● May 1, 2026
Boralex has 3,800 megawatts of wind, solar, hydro and battery energy storage assets, with more than 90% of them contracted for an average term of 10 years.
From The Wall Street Journal ● Mar. 25, 2026
The editor was still not hack from covering a plowing match; his mother said that the hydro maintenance crew covered a large area of the country...
From "The Incredible Journey" by Sheila Burnford
By choosing certain spots, each species is hydro- and thermoregulating, Muñoz says.
From Science Magazine ● Sep. 22, 2022
The energy business would encompass equipment and services for gas, coal and wind turbines, hydro-, nuclear and electric power generation.
From Reuters ● Nov. 10, 2021
Solar projects accounted for 60 percent of the projects, while hydro- electric plants were 75 percent of new capacity.
From BusinessWeek ● Sep. 8, 2011
It is considered probable that the cellulose nitrates are hydrocellulose derivatives, and experimental evidence in favour of this conclusion is supplied by the results of 'nitrating' the celluloses and their oxy- and hydro- derivatives.
From Researches on Cellulose 1895-1900 by C. F. Cross
In this building were also the medical offices, with a clinical laboratory and hydro- and electro-therapeutic equipment, and accommodations for from twelve to fifteen guests.
From How To Write Special Feature Articles A Handbook for Reporters, Correspondents and Free-Lance Writers Who Desire to Contribute to Popular Magazines and Magazine Sections of Newspapers by Willard Grosvenor Bleyer
South Korean utility Korea Hydro & Nuclear Power, for example, has signed a long-term supply agreement with Centrus.
From The Wall Street Journal ● Sep. 21, 2026
Find insight on gold futures, Talon Metals, Norsk Hydro and more in the latest Market Talks covering Basic Materials.
From The Wall Street Journal ● Sep. 14, 2026
At the Chilime Hydro tunnel, where Indian teams are deployed, rescuers entered 100 metres inside, but then said it was blocked.
From Barron's ● Aug. 31, 2026
Netball at the Hydro proved to be box office by selling 100,000 tickets.
From BBC ● Aug. 3, 2026
“I want to put some dog pee in his fancy Hydro Flask.”
From "Finding Junie Kim" by Ellen Oh
Earlier, I was told the hydros hover 4 or 5 inches over the water.
From Seattle Times ● Aug. 5, 2023
For that, you gotta wait for the hydros, another tradition we’ll have to explain.
From Seattle Times ● May 6, 2016
Eight classes of limited hydros compete both days, featuring Grand Prix supercharged boats competing for the championship cup at speeds of up to 160 miles an hour.
From Seattle Times ● Jun. 6, 2012
Last week, as 200,000 boat-racing buffs lined the shores of Seattle's Lake Washington, twelve of the big hydros took off after one another in the 54th annual Gold Cup regatta.
From Time Magazine Archive
She knew dozens of hydros, and warned me how to behave in them, while Mr. and Mrs. M'Leod stood aside and adored her.
From Actions and Reactions by Rudyard Kipling
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
