alkaloid

Etymology

It is formed from English alkali + -oid,^[2][3][4][5] after German Alkaloid, recorded from 1819 or earlier; compare French alcaloïde, from 1823 or earlier.^[2] Merriam-Webster Unabridged, the Shorter Oxford and the Oxford Dictionary of English take the word as German in origin.^[6][7][8] Klein calls it a hybrid, the second part being Ancient Greek -οειδής (-oeidḗs, “like”), from εἶδος (eîdos, “form, shape”).^[9] Alkali came through Medieval Latin alkali from Arabic اَلْقِلْي (al-qaly, “the ashes, soda ash”),^[3][2][1] related to قَلَى (qalā, “to fry, roast”).^[2][1]

Earliest recorded meaning

A naturally occurring organic compound with alkaline or basic properties: 1824, in a table in the Lancet.^[2] Etymonline also says by 1824, Merriam-Webster Unabridged gives 1820 and Dictionary.com 1825–35.^[3][6][5]

Semantic evolution

The name came soon after alkali took on its modern chemical sense, which Ayto and Etymonline date to 1813, in Humphry Davy.^[10][3] It first described compounds by their alkaline or basic behaviour; the OED notes that it now chiefly means a member of a large class of complex nitrogenous compounds of plant origin.^[2] A definition quoted by Etymonline stresses bitter taste and powerful effects on the animal system,^[3] and modern dictionaries likewise give morphine, strychnine, quinine, nicotine and caffeine as examples.^[11][7]

Timeline

• 1824 – noun, an organic compound with alkaline or basic properties.^[2][3]
• 1829 – attributive, of the nature of an alkaloid or containing one.^[2] Etymonline dates the adjective to 1844.^[3]

Meanings

Noun

1. Any of a large class of nitrogenous organic bases, found mainly in plants and usually physiologically active, such as morphine, quinine and nicotine.^{[11][6][7][2]}

Adjective

1. Of the nature of an alkaloid, or containing one.^[2][7]

Word family

• alkaloidal
• glycoalkaloid
• nonalkaloid

Related words

• alkali
• alkaline
• -oid

References

1. ^ a b c Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
5. ^ a b Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
6. ^ a b c Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
7. ^ a b c d Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
8. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
9. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
10. ^ Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
11. ^ a b Collins English Dictionary (2023), Glasgow: HarperCollins