Etymologically
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algae

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Pronunciation

  • UK: /ˈæl.ɡiː/, /ˈæl.dʒiː/[1]
  • US: /ˈæl.d͡ʒi/, /ˈæl.ɡi/[1]

Etymology

It is the plural of alga, borrowed from Latin alga (“seaweed”),[2][3][4][5] used in English in the Latin form, through New Latin.[6][7] The Latin word is of uncertain or unknown origin.[2][3][4][8] It has been connected with ulva (“a grass-like or rush-like water plant”), or traced to a root meaning "to putrefy, rot";[2][9] Klein derives it from Proto-Indo-European *el- (“to putrefy, rot”), comparing Norwegian ulka (“mouldy; slime”).[9] According to Etymonline, de Vaan finds the rot connection unlikely and suggests a foreign loanword.[2] Partridge thought it perhaps related to algeō (“to be cold”).[10]

Earliest recorded meaning

Seaweed: the singular alga is first recorded in L. Andrewe's translation of the Noble Lyfe, perhaps of 1527;[4] Barnhart and Merriam-Webster date it to 1551.[3][7] The plural algae is dated 1760 by Merriam-Webster[7] and 1794 by Etymonline and Barnhart.[2][3]

Semantic evolution

The word first meant simply seaweed, as in Latin.[4][11] Later it became a botanical term for a large and varied group of mainly aquatic organisms that photosynthesize but have no true stems, roots or leaves, ranging from single cells to the large seaweeds; in this sense it is used chiefly in the plural.[4][11][8] The algae were formerly classified as plants, and are now placed in other groups (Collins calls them protoctists).[8][7]

Timeline

  • c. 1527 – alga, a seaweed.[4]
  • 1551 – alga (Barnhart's and Merriam-Webster's date).[3][7]
  • 1760 – Algae, a major group of plants in former classifications.[7]
  • 1794 – the plural algae.[2][3]

Meanings

Noun

  1. (plural; singular alga) Simple organisms, from single cells to large seaweeds, that live chiefly in water or on damp surfaces, contain chlorophyll and other pigments, and lack true stems, roots and leaves; formerly classified as plants.[8][7][11]
  2. The mass formed by such organisms, as a green growth on water or stone: The pond was choked with algae by August.[11][4]

Word family

  • algal
  • alga

References

  1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  3. ^ a b c d e f Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
  4. ^ a b c d e f g Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
  5. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
  6. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
  7. ^ a b c d e f g Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
  8. ^ a b c d Collins English Dictionary (2023), Glasgow: HarperCollins
  9. ^ a b Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
  10. ^ Partridge, Eric (1966), Origins: A Short Etymological Dictionary of Modern English, 4th ed., London: Routledge & Kegan Paul
  11. ^ 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