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

Fifa has implemented drinks breaks at the midway point in each half for every game in this World Cup to allow players to hydrate.

From BBC • Jun. 11, 2026

"You could run into the extremes of eating too much, where if you're not drinking enough water to hydrate and exceed the amount of soluble and insoluble fiber, you can get constipated," Lee said.

From Science Daily • Mar. 8, 2026

Most sports demand constant motion, but skating involves working on a trick for maybe an hour, then desperately seeking cover from the sun to hydrate.

From The Wall Street Journal • Aug. 21, 2025

With our arms still buried under the compost, she brought ice-cold waters with straws up to our mouths so we could hydrate — a truly luxurious part of the service.

From Los Angeles Times • May 21, 2025

I wondered if it was wise to work up a sweat playing soccer/non-American football if you couldn’t hydrate after.

From "Darius the Great Is Not Okay" by Adib Khorram