hydroxide

Etymology

It is formed from English hydro- + oxide,^[2][3][4][5] with the combining form in its chemical use;^[2] Merriam-Webster counts it as International Scientific Vocabulary.^[4][6] Etymonline instead takes it from French hydroxide.^[7] Klein analyses it as parts of hydrogen and oxygen with the suffix -ide.^[8] Oxide is from oxide, coined in 1787 by Guyton de Morveau and Lavoisier from the first part of oxygène and the end of acide;^[7] the combining form comes from Ancient Greek ὑδρο- (hudro-), from ὕδωρ (húdōr, “water”).^[2][7]

Earliest recorded meaning

A compound of an element or radical with oxygen and hydrogen, rather than with water: 1851, in the Official Descriptive and Illustrated Catalogue of the Great Exhibition.^[2][4] Etymonline dates the word to 1830,^[7] and Dictionary.com to 1820–30.^[5]

Semantic evolution

In the OED's definition, some chemists restricted the term to compounds whose reactions show the presence of hydroxyl, the radical OH, which is named from 1869.^[2] The name of the ion itself, hydroxide ion, is recorded from 1955.^[2][3] Merriam-Webster Unabridged also applies the word to hydrated oxides regarded as containing hydroxide, such as aluminum hydroxide.^[4]

Timeline

• 1851 – a compound of an element or radical with oxygen and hydrogen.^[2][4] Etymonline gives 1830.^[7]
• 1955 – attributive, in hydroxide ion.^[2]

Meanings

Noun

1. (chemistry) The anion OH⁻, made up of one atom of hydrogen and one of oxygen; the hydroxide ion.^[4][3][1]
2. A compound containing this ion or the hydroxyl group, such as a base or alkali: sodium hydroxide.^[9][4][10]
3. A hydrated oxide regarded as containing hydroxide.^[4]

Word family

• aluminum hydroxide
• ammonium hydroxide
• barium hydroxide
• calcium hydroxide
• lithium hydroxide
• magnesium hydroxide
• potassium hydroxide
• sodium hydroxide

Related words

• hydroxyl
• hydrogen
• oxygen
• hydrate

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
4. ^ a b c d e f g h Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
5. ^ a b Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
6. ^ Gove, Philip Babcock, ed. (1961), Webster's Third New International Dictionary of the English Language, Unabridged, Springfield, Mass.: G. & C. Merriam
7. ^ a b c d e Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
8. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
9. ^ Collins English Dictionary (2023), Glasgow: HarperCollins
10. ^ The American Heritage Dictionary of the English Language (1992), 3rd ed., Boston: Houghton Mifflin