hydrate

American  

[hahy-dreyt] / ˈhaɪ dreɪt /

noun

hydrates plural

1. any of a class of compounds containing chemically combined water. In the case of some hydrates, as washing soda, Na 2 CO 3 ⋅10H 2 O, the water is loosely held and is easily lost on heating; in others, as sulfuric acid, SO 3 ⋅H 2 O, or H 2 SO 4 , it is strongly held as water of constitution.

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verb (used with or without object)

hydrates, present (3rd person singular) hydrated, past participle, past hydrating present participle

1. to combine chemically with water.

hydrate British  

/ ˈhaɪdreɪt /

noun

1. a chemical compound containing water that is chemically combined with a substance and can usually be expelled without changing the constitution of the substance

2. a chemical compound that can dissociate reversibly into water and another compound. For example sulphuric acid (H 2 SO 4 ) dissociates into sulphur trioxide (SO 3 ) and water (H 2 O)

3. (not in technical usage) a chemical compound, such as a carbohydrate, that contains hydrogen and oxygen atoms in the ratio two to one

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verb

1. to undergo or cause to undergo treatment or impregnation with water

hydrate Scientific  

/ hī′drāt′ /

1. A compound produced by combining a substance chemically with water. Many minerals and crystalline substances are hydrates.

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1. To combine a compound with water, especially to form a hydrate.

2. To supply water to a person in order to restore or maintain a balance of fluids.

Other Word Forms

Derived Forms

• hydration
  noun
• hydrator
  noun

Inflected Forms

Nouns

• hydrates
  plural

Participles

• hydrating
  present
• hydrated
  past

Conjugated Forms

Present

• hydrate
  simple
• hydrates
  simple
• have hydrated
  perfect
• has hydrated
  perfect
• am hydrating
  progressive
• are hydrating
  progressive
• is hydrating
  progressive
• have been hydrating
  perfect progressive
• has been hydrating
  perfect progressive

Past

• hydrated
  simple
• had hydrated
  perfect
• was hydrating
  progressive
• were hydrating
  progressive
• had been hydrating
  perfect progressive

Future

• will hydrate
  simple
• will have hydrated
  perfect
• will be hydrating
  progressive
• will have been hydrating
  perfect progressive

Etymology

Origin of hydrate

First recorded in 1795–1805; hydr- ¹ + -ate ²

Explanation

To hydrate is to add or absorb water. It's hot outside — don't forget to hydrate by drinking plenty of water! If you want to sound fancy, you can use the word hydrate every time you get a drink of water. Along with most organisms, we need to hydrate, or ingest water, to stay alive. This verb is also commonly used to mean "moisturize," as in "this magic cream will hydrate your skin like you won't believe!" As a noun, hydrate refers to a chemical compound that includes water molecules. A French chemist coined the noun in 1800 from the Greek hydor, "water."

Example Sentences

See Examples For:

hydrate hydrates hydrated hydrating

The word hydrate means that water molecules are built into the material's structure.

From Science Daily ● Aug. 1, 2026

Despite those conditions, the sodium vanadate hydrate continued to work effectively.

From Science Daily ● Aug. 1, 2026

Instead, the medical provider may just tell their patient to keep an eye on their symptoms, wait and hydrate.

From Los Angeles Times ● Jul. 24, 2026

Sleep, exercise, hydrate - do we really need to stick to recommended daily doses?

From BBC ● Jun. 20, 2026

We were always required to hydrate after being outside, especially in the summer.

From "The Season of Styx Malone" by Kekla Magoon

The world’s endowment of hydrocarbons is all but limitless, including unimaginable quantities of methane hydrates, not to mention that hydrocarbons can also be grown agriculturally.

From The Wall Street Journal ● Jan. 16, 2026

The bottom line is water is essential, hydrates us and has countless other health benefits.

From Salon ● Sep. 3, 2024

The challenge now is making sure everyone hydrates well to recover as quickly as possible.

From Washington Times ● Dec. 29, 2023

Developed by scientists at the University of Leeds, the saliva substitute is described as comparable to natural saliva in the way it hydrates the mouth and acts as a lubricant when food is chewed.

From Science Daily ● Nov. 20, 2023

The parts that remain are likely to be converted into oxides, carbonates, and hydrates, through reaction with oxygen, carbon dioxide, and water, which are always present at the surface and at shallow depths.

From The Economic Aspect of Geology by Leith, C. K. (Charles Kenneth)

The hydrated material stored far more charge, charged much faster, and continued to perform reliably for more than 400 charge cycles.

From Science Daily ● Aug. 1, 2026

Thousands of displaced residents are now staying in evacuation centres - though the challenge is to keep them cool and hydrated as the region battles sweltering heat.

From BBC ● Jul. 30, 2026

"We are urging people to stay hydrated and use air conditioners," a fire brigade spokesman told AFP.

From Barron's ● Jul. 23, 2026

What’s more, staying hydrated helps flush toxins, keeps organs functioning optimally and thins mucus, making it easier for lungs to stay clear.

From The Wall Street Journal ● Jul. 23, 2026

I actually don’t feel like drinking, but I hear Kyro’s voice in my head: Be smart—stay hydrated and keep your fuel up.

From "The Running Dream" by Wendelin Van Draanen

The fruit is also made up of about 92% water, making it a hydrating option during hot weather or after exercise.

From Science Daily ● May 17, 2026

WSJ | Buy Side: Using powerful but gentle ingredients, this body wash kills bacteria while soothing and hydrating skin.

From The Wall Street Journal ● May 6, 2026

That brief chill allows the fat to firm and the panade to finish its quiet work, hydrating and binding.

From Salon ● Mar. 11, 2026

If you're going to use an eye cream, Tina recommends looking for one with hydrating ingredients alongside the caffeine as that supports skin quality.

From BBC ● Feb. 16, 2026

She produced an oblong cake of soap in a black case, a hydrating mask, a vial of cell renewal drops, and two tubes of face cream.

From "Interpreter of Maladies" by Jhumpa Lahiri