microorganism

Etymology

It is formed from English micro- + organism,^[2][3][4][5] perhaps after French micro-organisme, recorded in 1876.^[2] Merriam-Webster classes it as International Scientific Vocabulary.^[6] The prefix comes from Ancient Greek μικρός (mikrós, “small”),^[7] and organism goes back through New Latin organismus to Ancient Greek ὄργανον (órganon).^[8]

Earliest recorded meaning

An organism so small that it can be seen only through a microscope: 1880, in W. MacCormac's Antiseptic Surgery.^[2] Barnhart and Merriam-Webster also date it to 1880,^[3][6] and Dictionary.com to 1875–80.^[5]

Timeline

• 1880 – an organism of microscopic size.^[2][3][6]

Meanings

Noun

1. An organism too small to be seen without a microscope, such as a bacterium, protozoan, fungus or alga.^[2][6][9] Collins also counts viruses.^[10]

Related words

• microbe
• organism
• organ
• micro-

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
4. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
5. ^ a b Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
6. ^ a b c d Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
7. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
8. ^ Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
9. ^ The American Heritage Dictionary of the English Language (1992), 3rd ed., Boston: Houghton Mifflin
10. ^ Collins English Dictionary (2023), Glasgow: HarperCollins