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hydrate

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Etymology and origin of the English word hydrate

Confidence
Established
Formation
Borrowing
First attested
1802 J. Smithson, in the Philosophical Transactions of the Royal Society More words from the 19th century
Borrowed from
French hydrate
Ultimate origin
Ancient Greek ὕδωρ
Derivations

Pronunciation

  • /haɪˈdɹeɪt/, /ˈhaɪdɹeɪt/[1]

Etymology

The noun is borrowed from French hydrate,[2][3][4][5] coined about 1800 by the French chemist Joseph-Louis Proust[2][6][3] from Ancient Greek ὕδωρ (húdōr, “water”), stem ὑδρ- (hudr-),[2][5][7] and the chemical suffix -ate, of Latin origin;[6] Klein calls it a hybrid.[6] The OED treats it as formed directly from the Greek word and the English suffix, comparing the French,[7] and Merriam-Webster Unabridged labels it International Scientific Vocabulary, from hydr-.[8] The Greek word is from a suffixed form of Proto-Indo-European *wed- (“water; wet”).[2] The verb was formed from the noun,[7][4][3] perhaps modelled on the French verb hydrater.[2][7]

Earliest recorded meaning

A compound of water with another substance: 1802, in a paper by J. Smithson in the Philosophical Transactions of the Royal Society.[7] Etymonline and Barnhart also date the noun to 1802.[2][3]

Semantic evolution

The noun was formerly used also for a hydroxide, such as potassium hydroxide,[7][8] and for compounds formed on the same pattern as water.[2] Collins notes a non-technical use for a compound, such as a carbohydrate, that has hydrogen and oxygen atoms in the ratio two to one.[9] The verb is implied in hydrated in 1812, according to Etymonline;[2] the OED's first record of it, "to combine chemically with water", is from 1850,[7][3] while Merriam-Webster Unabridged dates that sense to 1846.[8] An intransitive use followed in the 20th century (1909).[7] The physiological sense, to make a person take in enough fluid, is recorded from 1942 in a medical journal,[7] and Etymonline and Barnhart date "to restore moisture" to 1947, Barnhart of food products.[2][3] Since 1954, first in an advertisement, cosmetics have been said to hydrate the skin or hair.[7]

Timeline

  • 1802 – noun, a compound of water with another substance.[7][2][3]
  • 1812 – hydrated, combined chemically with water.[2]
  • 1850 – verb, to combine chemically with water.[7][3] Merriam-Webster Unabridged dates the sense to 1846.[8]
  • 1909 – intransitive, to become combined with water.[7]
  • 1942 – to make a person take in enough fluid.[7]
  • 1947 – to restore moisture to something, such as a dried food.[3][2]
  • 1954 – to moisturize the skin or hair.[7]

Meanings

Noun

  1. A chemical compound in which water is combined with another substance and can usually be driven off without changing that substance's constitution.[9][8][7][4]
  2. A compound that can split reversibly into water and another compound.[9]
  3. A hydroxide (an older use).[7][8]

Verb

  1. To combine chemically with water; to convert into a hydrate.[8][7][4]
  2. Intransitive: to become combined with water.[7][4]
  3. To supply the body with enough fluid, especially by drinking water; also reflexive and intransitive: Cyclists need to hydrate well on hot days.[8][7]
  4. To moisturize the skin or hair with a cosmetic.[7]
  5. In papermaking, to beat pulp for a long time, as in making glassine.[8]

Word family

References

  1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g h i j k l Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  3. ^ a b c d e f g h i Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
  4. ^ a b c d e Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
  5. ^ a b Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
  6. ^ a b c Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
  7. ^ a b c d e f g h i j k l m n o p q r s t u Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
  8. ^ a b c d e f g h i Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
  9. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins

Related etymologies

Cite this entry

“Hydrate.” Etymologically, 8 Nov. 2026, etymologically.com/en/hydrate. Accessed 9 Nov. 2026.

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