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 /
noun
Hydro
2
British
/ ˈhaɪdrəʊ /
noun
hydro-
3
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
4
British
/ ˈhaɪdrəʊ /
adjective
noun
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:
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
Much of that weak performance has to do with lower hydro generation, RBC’s Alexander Wheeler and Ziyad Jasimuddin write in a note.
From The Wall Street Journal ● Mar. 18, 2026
"There's enormous potential. We did a study which identified 20 potential hydro sites in Rhondda Cynon Taf alone," he said.
From BBC ● Feb. 24, 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
But enough of these follies: ‘Necro-, pyro-, geo-, hydro-, cheiro-, coscinomancy, With other vain and superstitious sciences.’
From Witch, Warlock, and Magician Historical Sketches of Magic and Witchcraft in England and Scotland by W. H. Davenport (William Henry Davenport) Adams
Another class begins with hydro- from the Greek word for water.
From Society for Pure English Tract 4 The Pronunciation of English Words Derived from the Latin by John Sargeaunt
Hydro One, a utility company based in Toronto, said in a post on X that the name appeared due to their use of a third-party mapping service.
From BBC ● Aug. 31, 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
The sight of the King and Queen emerging from a Tardis at the start of the opening ceremony in the Hydro stunned the audience.
From BBC ● Aug. 3, 2026
Simple Minds brought the curtain down on an 11-day sporting festival during the closing ceremony at the Hydro on Sunday.
From BBC ● Aug. 3, 2026
He bought a ticket and traveled down the lake on Hydro, leaning over the rail, with one eye on the minute hand of his watch.
From "Bomb" by Steve Sheinkin
More than one fan compares watching hydros to watching bowling, but less interesting.
From Seattle Times ● Sep. 17, 2017
Even now, 40 or 50 years later, you can still tell a true native Seattleite by how excited he or she gets when they tell you about dragging hydros behind their bikes.”
From Seattle Times ● Jul. 27, 2013
The pirates are sober and nicer, the newer turbine-powered hydros are quieter and safer.
From Seattle Times ● Jul. 27, 2013
As in the case of big TVA it finally boiled down to how the PWA "hydros" could market their power.
From Time Magazine Archive
Changed "hydros" to "hydrous" in the footnote on page 565: "the hydrous sulphate."
From De Re Metallica, Translated from the First Latin Edition of 1556 by Georgius Agricola
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.
