hydro
1 Americannoun
plural
hydros-
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
adjective
noun
combining form
-
indicating or denoting water, liquid, or fluid
hydrolysis
hydrodynamics
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indicating the presence of hydrogen in a chemical compound
hydrochloric acid
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indicating a hydroid
hydrozoan
noun
noun
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-.
Etymology
Origin of hydro1
1880–85; by shortening of compounds with hydro- 1 ( -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.
Its 2025 performance was driven by record levels of biomass generation, pellet production and earnings from its hydro unit, they say.
This is supported by record high hydro reserves—energy which hasn’t been sold yet—of 9 Terawatt hours.
"There's enormous potential. We did a study which identified 20 potential hydro sites in Rhondda Cynon Taf alone," he said.
From BBC
In 2025, Alphabet approached Brookfield Renewable to secure three gigawatts of hydro power External link.
From Barron's
In the pitch black of the mine, mud-splattered men with headlamps drill into the rock in two-man teams, using hydro drills with long, thin nozzles that shoot out pressurized water to loosen the ore.
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.
