epidemiology

Etymology

It is from Ancient Greek ἐπιδήμιος (epidḗmios, “among the people; epidemic”) with the combining form -logy, in the OED's and Etymonline's analysis.^[2][3][4] The Shorter Oxford and the Oxford Dictionary of English start instead from ἐπιδημία (epidēmía, “prevalence of a disease”),^[5][6] the American Heritage Dictionary from Medieval Latin epidēmia (“an epidemic”),^[7] and Dictionary.com from epidemic.^[8] The OED compares earlier New Latin epidemiologia (1598 or earlier), French épidémiologie (1803) and German Epidemiologie (1795).^[2] The Greek words are formed from ἐπί (epí, “among, upon”) and δῆμος (dêmos, “people, district”).^[3]

Earliest recorded meaning

The study of epidemic diseases: 1850, as a heading in the London Journal of Medicine.^[2][3] Merriam-Webster dates the word to about 1860, and the Shorter Oxford to the late 19th century.^[9][5]

Semantic evolution

At first the word meant only the study of epidemics.^[2][3] In later use it widened to the branch of medicine that studies how often diseases and other health conditions occur in populations, how they are distributed and what determines them.^[2][5] It also came to mean the pattern of occurrence of one disease, the factors that govern its presence or absence.^[9][5]

Timeline

• 1850 – the study of epidemic diseases.^[2][3]

Meanings

Noun

1. The branch of medicine that studies the incidence, distribution and control of diseases in populations.^{[10][9][2][5]}
2. The factors that govern the occurrence and spread of a particular disease: the epidemiology of tuberculosis.^[9][5]

Word family

• epidemiologic
• epidemiologically
• epidemiologist

Related words

• epidemic
• epidemy
• demotic

References

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