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con·​jec·​ture kən-ˈjek-chər How to pronounce conjecture (audio)
: inference formed without proof or sufficient evidence
: a conclusion deduced by surmise or guesswork
The criminal's motive remains a matter of conjecture.
: a proposition (as in mathematics) before it has been proved or disproved
: interpretation of omens


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conjectured; conjecturing kən-ˈjek-chə-riŋ How to pronounce conjecture (audio)

transitive verb

: to arrive at or deduce by surmise or guesswork : guess
scientists conjecturing that a disease is caused by a defective gene
: to make conjectures as to
conjecture the meaning of a statement
conjecturer noun

Did you know?

When the noun conjecture entered English in the 14th century, it referred to the act of interpreting signs or omens especially to make prognostications. That sense is now obsolete, but by the 16th century both the noun and verb conjecture had acquired the meanings of speculation and inference that we use today. Conjecture derives via Middle English and Middle French from the Latin verb conicere ("to throw together"), a combination of com- ("together") and jacere ("to throw").

Examples of conjecture in a Sentence

Noun Whether Columbus brought syphilis to the New World—or to the Old World—has been the subject of conjecture for at least 500 years. Carl Zimmer, Science, 11 May 2001
… their voices rose in a chorus of conjecture and alarm, repeating the selfsame remark: "What is she going to do? I mean, is Betty going to faint?" Edna O'Brien, New Yorker, 1 Jan. 1990
The reason why the French with superior man-power and American resources were doing so poorly was not beyond all conjecture. Barbara W. Tuchman, The March of Folly, 1984
Peculiar features of early maps, which may have been nothing but a draftsman's whimsy, have inspired pages of vain conjecture. Samuel Eliot Morison, The European Discovery of America, 1971
The biography includes conjectures about the writer's earliest ambitions. a conjecture about the extent of the injury Most of the book is conjecture, not fact. Verb It is fashionable now to conjecture that the Big Bang was caused by a random quantum fluctuation in a vacuum devoid of space and time. Martin Gardner, Skeptical Inquirer, November/December 1998
… their traces left for future archaeologists to rediscover and perhaps to wonder or conjecture over. Jane Jacobs, Cities and the Wealth of Nations, 1984
I am anxious to conjecture beforehand what may be expected from the sowing turneps [sic] in jaded ground, how much from the acre, & how large they will be? Thomas Jefferson, letter, 29 Dec. 1794
Some have conjectured that the distant planet could sustain life. We only conjecture about his motives. See More
Recent Examples on the Web
That combination fueled conjecture that Cameron would be able to bridge the Republican Party's warring factions. Tal Axelrod, ABC News, 7 Nov. 2023 And indeed, there was likely very little hope of ever proving this moonshine conjecture. Manon Bischoff, Scientific American, 5 Feb. 2024 Artificial intelligence is only beginning to be used to formulate substantive conjectures and prove significant mathematical results. Quanta Magazine, 26 Jan. 2024 That is conjecture, a gambit that has no place in medicine or any other science. Sun Sentinel Editorial Board, Sun Sentinel, 10 Jan. 2024 The conjecture itself is quite abstract and requires advanced mathematics. Manon Bischoff, Scientific American, 24 Jan. 2024 The first half of Season 6 deals with the lead-up to the Paris car crash that killed Diana and her then-boyfriend Dodi Fayed (Khalid Abdalla), in 1997, and there has been endless conjecture over whether or not Morgan will portray the moment of the princess’s death. K.j. Yossman, Variety, 25 Oct. 2023 Some of the leading conjectures are these: •The aftershocks of the pandemic: About 7 million deaths globally were attributed to COVID-19, and there were possibly as many as 20 million. Marshall Ingwerson, The Christian Science Monitor, 22 Dec. 2023 Solving this conjecture would not be rewarded with a million dollars or euros but with fame and honor in the math community. Manon Bischoff, Scientific American, 16 Nov. 2023
One reason for the disparity could be that members of large Latino communities near South Pasadena are arrested while driving through the city, Harris conjectured. Noah Goldberg, Los Angeles Times, 14 Feb. 2024 Share this article Newsletter Get Quanta Magazine delivered to your inbox Introduction Shortly before his death, Schramm conjectured that Grimmett and Marstrand’s theorem could be generalized. Quanta Magazine, 18 Dec. 2023 Schramm conjectured that the phase transition in a process called percolation can be estimated by using only a close-up view of the system — called the local perspective — for many important mathematical structures. Quanta Magazine, 18 Dec. 2023 The feverish conjecturing among Mr. Trump’s allies was reignited this weekend, when ABC News revealed some of the first details of what Mr. Meadows told federal prosecutors. Maggie Haberman, New York Times, 22 Aug. 2023 The feverish conjecturing among Trump’s allies was reignited this weekend when ABC News revealed some of the first details of what Meadows told federal prosecutors. Jonathan Swan,, 22 Aug. 2023 Introduction In 1961, the logician Hao Wang conjectured that if a set of shapes tiles the plane, then the shapes must be able to tile the plane periodically. Quanta Magazine, 30 Oct. 2023 The researchers conjectured this was because of a flaw in the machine learning systems. Rayna Reid Rayford, Essence, 9 Oct. 2023 Trades conjectured that this late-in-the-year deal means people may be working in Hollywood through the holidays, something almost unheard of by custom. Vulture, 27 Sep. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'conjecture.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Noun and Verb

Middle English, from Middle French or Latin; Middle French, from Latin conjectura, from conjectus, past participle of conicere, literally, to throw together, from com- + jacere to throw — more at jet

First Known Use


14th century, in the meaning defined at sense 2


15th century, in the meaning defined at transitive sense 1

Time Traveler
The first known use of conjecture was in the 14th century

Dictionary Entries Near conjecture

Cite this Entry

“Conjecture.” Dictionary, Merriam-Webster, Accessed 3 Mar. 2024.

Kids Definition


1 of 2 noun
con·​jec·​ture kən-ˈjek-chər How to pronounce conjecture (audio)
: an opinion or judgment based on little or no evidence


2 of 2 verb
conjectured; conjecturing
conjecturer noun

More from Merriam-Webster on conjecture

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