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• hydro
  hydro

  noun

  hydroelectric power.
• hydro-
  hydro-

  a combining form meaning “water,” used in the formation of compound words.
• Hydro
  Hydro

  noun

  (esp in Canada) a hydroelectric power company or board
• hydro–
  hydro–

  A prefix that means: “water” (as in hydroelectric) or “hydrogen,” (as in hydrochloride).

hydro

¹ American  

[hahy-droh] / ˈhaɪ droʊ /

noun

hydros plural

1. Informal. hydroelectric power.

2. Informal. hydroplane.

3. British.

   1. a bathhouse, hotel, or resort catering to people taking mineral-water health cures; spa.

   2. an establishment furnishing hydrotherapy.

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adjective

1. Informal. of, relating to, or furnishing water, water power, or hydroelectricity.

   funds for new hydro projects.

hydro- ² American  

1. a combining form meaning “water,” used in the formation of compound words.

   hydroplane; hydrogen.

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hydro- ³ American  

1. a combining form representing hydrogen in compound words, denoting especially a combination of hydrogen with some negative element or radical.

   hydrobromic.

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hydro- ¹ British  

combining form

1. indicating or denoting water, liquid, or fluid

   hydrolysis

   hydrodynamics

2. indicating the presence of hydrogen in a chemical compound

   hydrochloric acid

3. indicating a hydroid

   hydrozoan

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Hydro ² British  

/ ˈhaɪdrəʊ /

noun

1. (esp in Canada) a hydroelectric power company or board

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hydro ³ British  

/ ˈhaɪdrəʊ /

adjective

1. short for hydroelectric

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noun

1. a Canadian name for electricity when it is supplied to a residence, business, institution, etc

hydro ⁴ British  

/ ˈhaɪdrəʊ /

noun

1. (esp formerly) a hotel or resort, often near a spa, offering facilities for hydropathic treatment

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hydro– Scientific  

1. A prefix that means: “water” (as in hydroelectric) or “hydrogen,” (as in hydrochloride).

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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 ( cf. -o); hydro ( def. 4 ) hydro- ¹ analyzed as an adj.

Origin of hydro-²

< Greek, combining form of hýdōr water

Example Sentences

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

They are given names consisting of the prefix hydro-, the name of the second element present, and the termination -ic.

From An Elementary Study of Chemistry by McPherson, William

Other Series.—In addition to the two series of hydro- carbons above given, CnH2n+2 and CnH2n, other series are known with the general formulm CnH2n-2, CnH2n-4, CnH2n-6, CnH2n-8, etc., as far as CnH2n-32, or C26H2O.

From An Introduction to Chemical Science by Williams, Rufus Phillips