coincide

Etymology

It is borrowed from Medieval Latin coincidō (“to fall together”), a verb of astrology,^{[2][3][4][5][6]} and in part borrowed from French coïncider, which the OED and Barnhart give as the immediate source.^[2][7][8] The Medieval Latin verb is formed from co- (“together”) and incidō (“to fall upon or into; to happen”),^[2][3][5][9] itself from in- (“upon”) and cadō (“to fall”),^{[3][7][9][10]} from Proto-Indo-European *kad- (“to fall”).^[3] In the 17th century the Latin verb itself was used in English, unchanged.^[2][3]

Earliest recorded meaning

To fall in together, to collapse: Nehemiah Grew used it in this sense in 1673, but it did not last.^[2] The lasting senses begin with "to be identical in substance or nature" (1705, in Berkeley) and "to occupy the same space, to agree in position" (1715, in George Cheyne).^[2][3][11]

Semantic evolution

The first senses were spatial and logical: two figures that coincide occupy the same space, as with superposed triangles in Euclid, and two things that coincide agree exactly in nature.^[2][12] Johnson (1755) gave "to fall upon the same point" and "to concur; to be consistent with", quoting Cheyne on the equator and the ecliptic.^[13] The temporal sense, "to happen at the same time", is not found until 1809,^[2][3] and the use of people agreeing in opinion is from 1808.^[2] The noun coincidence is older than the verb, from 1605, and coincident from the 16th century.^[7][9]

Timeline

• 1640s – the Latin verb coincidere used in English.^[3]
• 1673 – to fall in together, collapse (obsolete).^[2]
• 1705 – to be identical in substance or nature; to agree exactly.^[2][3][11]
• 1715 – to occupy the same space, to agree in position.^[2][3]
• 1808 – of persons, to agree in opinion.^[2]
• 1809 – to happen at the same time.^[2][3]

Meanings

Verb

1. To happen at the same time, or to occupy the same period: Her visit coincided with the town's spring fair.^[14][11][2]
2. To occupy the same place in space, or a corresponding position on a scale: When the two triangles are laid together, their sides coincide.^[11][2]
3. To be identical or correspond exactly in nature or character; to agree: Our views on the matter coincide.^[14][11][2]
4. Of people, to agree in opinion or feeling.^[2][14]

Word family

• coincident
• coincidence

Related words

• incident
• accident
• chance
• cadence

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k l m n o p q r Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e f g h i j k Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
5. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
6. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
7. ^ a b c Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
8. ^ Weekley, Ernest (1921), An Etymological Dictionary of Modern English, London: John Murray
9. ^ a b c Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
10. ^ Skeat, Walter W. (1911), A Concise Etymological Dictionary of the English Language, new ed., Oxford: Clarendon Press
11. ^ a b c d e Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
12. ^ Cresswell, Julia (2021), Oxford Dictionary of Word Origins, 3rd ed., Oxford: Oxford University Press
13. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
14. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins