incidence

Etymology

It is inherited from Middle English incidence,^[2] borrowed from Old French incidence,^[3][4][5][2] which the OED derives from the French adjective incident;^[3][6] Etymonline, Dictionary.com and Merriam-Webster trace it further to Late Latin incidentia,^[4][7][8] and the Shorter Oxford and the Oxford Dictionary of English allow a direct borrowing of Medieval Latin incidentia.^[5][9] The Anglo-Norman Dictionary records incidence from about 1300, meaning an incident or episode.^[10] The Latin noun is formed from the stem of incidēns, present participle of incidō (“to fall upon, happen, befall”),^[4][8][9] from in- (“on”) and cadō (“to fall”), from Proto-Indo-European *kad- (“to fall”).^[4]

Earliest recorded meaning

Incidental matter, a digression: in The Kingis Quair (1423), where the poet goes back to his subject and leaves "all incidence".^[3][2] Etymonline dates this sense to the early 15th century.^[4]

Semantic evolution

The first senses, an incidental matter (1423–1650) and a casual circumstance (1670), are obsolete.^[3][5] The physical sense, the falling of a ray of light or a moving body on a surface, is recorded from 1626, in Bacon's Sylva Sylvarum,^[3][8][4] and the general sense of falling upon or affecting something from 1656.^[3][4] In 1825 the economist J. R. McCulloch used it for the way the burden of a tax falls;^[3] from 1846 it meant the range or scope of a thing's effects.^[3] The usual modern sense, how often something occurs, especially a disease or a crime, dates from the early 19th century.^[9][5]

Timeline

• 1423 – incidental matter (obsolete by 1650).^[3]
• 1626 – the falling of a ray or a moving body on a surface.^[3][8]
• 1652 – liability or natural tendency (obsolete).^[3]
• 1656 – the act or fact of falling upon or affecting something.^[3][4]
• 1670 – a casual circumstance (obsolete).^[3]
• 1728 – in astronomy, immersion in an eclipse.^[3]
• 1825 – the way the burden of a tax falls.^[3]
• 1846 – the range or scope of a thing's influence.^[3]
• early 19th century – the rate or frequency of occurrence.^[9][5]
• 1906 – an incident, in Arkansas English.^[11]

Meanings

Noun

1. The rate or frequency with which something happens: a rising incidence of measles in the region.^[12][8][13]
2. The act or fact of happening; occurrence.^[13][8]
3. The way in which something falls upon or affects people or things, especially the way the burden of a tax is distributed.^[12][3][5]
4. In physics, the arrival of a ray, beam or projectile at a surface; also, the angle of incidence.^{[12][13][8][3]}
5. In geometry, the partial coincidence of two figures, as of a point lying on a line.^[12][3]
6. (chiefly dialect) An incident.^[8][11]
7. (obsolete, 1423–1650) An incidental or subordinate matter.^[3][5][2]

Word family

• angle of incidence

Related words

• incident
• incidental
• coincidence
• accident
• cadence

Usage notes

Merriam-Webster marks the sense "an incident" as now chiefly dialectal;^[8] the Dictionary of American Regional English records it from Arkansas in 1906 and thinks it was probably influenced by coincidence.^[11]

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
3. ^ a b c d e f g h i j k l m n o p q r s t Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
4. ^ a b c d e f g h Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
5. ^ a b c d e f g Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
6. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
7. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
8. ^ a b c d e f g h i Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
9. ^ a b c d Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
10. ^ Anglo-Norman Dictionary (AND2), Aberystwyth University, anglo-norman.net (2nd ed., 2005–)
11. ^ a b c Cassidy, Frederic G. & Joan Houston Hall (eds.) (1985–2002), Dictionary of American Regional English, vols I–IV, Cambridge, Mass.: Belknap Press of Harvard University Press
12. ^ a b c d Collins English Dictionary (2023), Glasgow: HarperCollins
13. ^ a b c The American Heritage Dictionary of the English Language (1992), 3rd ed., Boston: Houghton Mifflin