for·​ni·​ca·​tion | \ ˌfȯr-nə-ˈkā-shən How to pronounce fornication (audio) \

Definition of fornication

: consensual (see consensual sense 2) sexual intercourse between two persons not married to each other — compare adultery

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What’s the difference between adultery and fornication?

In case you were wondering, the words adultery and adult are not etymologically related (in other words, adultery didn’t grow out of adult in the way that punditry grew out of pundit). Although both words come from Latin and share the same first five letters, adultery is from adulterāre (“to pollute, defile, commit adultery”), a word formed ultimately from the Latin elements ad- “to, near” and alter “other.” English adult comes from adultus, which is the past participle of the Latin word adolescere (“to grow up”).

In legal use there is a difference between adultery and fornication. Adultery is only used when at least one of the parties involved (either male or female) is married, whereas fornication may be used to describe two people who are unmarried (to each other or anyone else) engaging in consensual sexual intercourse.

Examples of fornication in a Sentence

Recent Examples on the Web The film begins with diversion — a triangle involving Juan’s teenage son — and moves on to Juan’s voyeurism, encouraging Esther to fornication and exhibitionism. Armond White, National Review, "Franco Zeffirelli: Unlikely Conservative Hero," 20 June 2019 In Paris and London, adultery, fornication, and prostitution spiked. Cate Mcquaid,, "MFA’s ‘Casanova’ a voluptuous look at a notorious voluptuary," 6 July 2018 Johanna Luthman, a historian at the University of North Georgia, has worked for years to understand the practice and repercussions of fornication, adultery and bastardy among the early 17th-century English aristocracy. Richard Davenport-hines, WSJ, "When Adultery Meant Exile," 11 Aug. 2017 These 10 movies and TV shows particularly oversell poolside fornication. Christopher Rosa, Glamour, "Movies and TV Shows That Make Pool Sex Look Way Hotter Than It Actually Is," 7 July 2017 Practices that were once crimes, like fornication and adultery, or that are still crimes, like incest, infanticide, and rape, generally lie outside the scope of his concern. Jill Lepore, The New Yorker, "Weaponizing the Past," 27 Mar. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'fornication.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of fornication

14th century, in the meaning defined above

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Time Traveler for fornication

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The first known use of fornication was in the 14th century

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Cite this Entry

“Fornication.” Dictionary, Merriam-Webster, Accessed 29 Oct. 2020.

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More Definitions for fornication


for·​ni·​ca·​tion | \ ˌfȯr-nə-ˈkā-shən How to pronounce fornication (audio) \

Medical Definition of fornication

: consensual sexual intercourse between two persons not married to each other


for·​ni·​ca·​tion | \ ˌfȯr-nə-ˈkā-shən How to pronounce fornication (audio) \

Legal Definition of fornication

: consensual sexual intercourse between a man and especially single woman who are not married to each other also : the crime of engaging in fornication — compare adultery

Note: Where still considered a crime, fornication is classified as a misdemeanor.

History and Etymology for fornication

Late Latin fornicatio, from fornicare to have intercourse with prostitutes, from Latin fornic-, fornix arch, vault, brothel

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