epidemic

Etymology

It is borrowed from Middle French épidémique (recorded in Middle French from 1565, and in another spelling from 1544), or its source Medieval Latin epidēmicus, found in a British text of the 13th century.^[2] The French adjective is formed on épidémie (“an epidemic disease”),^[3][4][5] from Late Latin epidēmia,^[6][7][8] from Ancient Greek ἐπιδημία (epidēmía, “a stay in a place; the prevalence of a disease”), especially the plague,^[3][4] a noun formed on ἐπιδήμιος (epidḗmios, “prevalent, among the people”).^[5][6][9] Its parts are ἐπί (epí, “among, upon”) and δῆμος (dêmos, “people, district”), the word behind democracy.^[3][6][7] The noun epidemic is simply the adjective used as a noun.^[3][4]

Earliest recorded meaning

Of an acute disease: attacking many people in a population within a short time: 1603, in Thomas Lodge's Treatise of the Plague.^[2][10] Etymonline dates the adjective to about 1600, "common to or affecting a whole people", and notes that it was used of diseases from the start, although nothing in its Greek parts restricts it to them.^[3]

Semantic evolution

English already had the idea before it had this word: Barnhart finds an older noun epideme, an epidemic disease, in the Paston Letters in 1472,^[4] and Etymonline notes that the older language used Old English man-cwealm for a deadly pestilence.^[3] The adjective soon passed from disease to anything undesirable that spreads widely, as early as 1617.^[2][11] A noun use for such a widespread outbreak, in a figurative sense, is recorded from 1630, and for an epidemic disease from 1666;^[2] Barnhart and Etymonline date the noun to 1757.^[4][3] In the 18th century the word began to cover health conditions and behaviour that are not infectious but are spreading, such as heavy drinking (1744), and in the 19th century outbreaks of parasites and pests (1864).^[2] Phrases like epidemic proportions, for a very high rate of something, go back to 1850.^[2]

Timeline

• 1472 – the older noun epideme, an epidemic disease, in the Paston Letters.^[4]
• 1603 – the adjective, of a disease attacking many people at once.^[2][10]
• 1617 – figuratively, of anything undesirable: widespread.^[2]
• 1630 – the noun, a sudden widespread occurrence of something.^[2]
• 1666 – the noun, an epidemic disease;^[2] 1757 in Barnhart and Etymonline.^[4][3]
• 1744 – of a non-infectious condition or behaviour that is spreading.^[2]
• 1850 – epidemic levels, epidemic proportions, of a very high rate.^[2]
• 1864 – a sudden infestation of parasites or upsurge of a pest.^[2]

Modern meaning

Adjective

1. Of a disease: affecting many people in a community or region at the same time: Typhus was epidemic in the camps that winter.
2. Widespread and spreading fast, usually of something unwelcome.

Noun

1. A widespread outbreak of an infectious disease: A measles epidemic closed the village school.
2. A rapid spread or growth of something, especially something unpleasant: an epidemic of burglaries.

Word family

• epidemically
• epidemical
• epidemicity
• interepidemic
• preepidemic

Related words

• ecdemic
• endemic
• pandemic
• epidemiology
• democracy
• demotic

Usage notes

Merriam-Webster distinguishes epidemic, a disease affecting many people in an area at one time, from endemic, a disease constantly present in one region.^[10]

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k l m Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e f g h Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b c d e f g Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
5. ^ a b Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
6. ^ a b c Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
7. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
8. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
9. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
10. ^ a b c Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
11. ^ Kay, Christian; Roberts, Jane; Samuels, Michael; Wotherspoon, Irené, eds. (2009), Historical Thesaurus of the Oxford English Dictionary, Oxford: Oxford University Press; online edition (2024)