hydrate

American  

[hahy-dreyt] / ˈhaɪ dreɪt /

noun

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)

hydrated, hydrating

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

• hydration noun
• hydrator noun

Etymology

Origin of hydrate

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

Example Sentences

"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

Thomson described how her mother refused to drink, despite desperate efforts from her family to hydrate her with a syringe, and was spitting out her saliva every five to 10 seconds until she died.

From BBC • Mar. 4, 2026

Coming around the 30th and 75th minutes, the pauses in play allow teams to hydrate and use ice towels.

From The Wall Street Journal • Jun. 27, 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

Mother called a hospital in Utah and begged them to give her an IV. “I need to hydrate him,” she said.

From "Educated" by Tara Westover