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Which thinker made an important conjecture about prime numbers?

conjecture

American  
[kuhn-jek-cher] / kənˈdʒɛk tʃər /

noun

  • conjectures
    plural
  1. the formation or expression of an opinion or theory without sufficient evidence for proof.

  2. an opinion or theory so formed or expressed; guess; speculation.

    Synonyms:
    hypothesis, theory, supposition, inference, surmise
  3. Obsolete. the interpretation of signs or omens.


verb (used with object)

  • conjectures,
    present (3rd person singular)
  • conjectured,
    past participle,  past
  • conjecturing
    present participle
  1. to conclude or suppose from grounds or evidence insufficient to ensure reliability.

    Synonyms:
    presume, suppose, surmise

verb (used without object)

  • conjectures,
    present (3rd person singular)
  • conjectured,
    past participle,  past
  • conjecturing
    present participle
  1. to form conjectures.

conjecture British  
/ kənˈdʒɛktʃə /

noun

  1. the formation of conclusions from incomplete evidence; guess

  2. the inference or conclusion so formed

  3. obsolete interpretation of occult signs

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

verb

  1. to infer or arrive at (an opinion, conclusion, etc) from incomplete evidence

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Synonym Usage

See guess.

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Etymology

Origin of conjecture

First recorded in 1350–1400; (for the noun) Middle English, from Middle French, from Latin conjectūra “inference, reasoning,” from conject(us) “thrown together” (past participle of conicere, conjicere “to throw together, form a conclusion,” from con- con- + -icere, -jicere, combining form of jacere “to throw”) + -ūra -ure; (for the verb) late Middle English conjecturen, from Middle French, from Late Latin conjecturāre, derivative of the noun

Explanation

Can you guess what conjecture means? It's a word to use when you are not sure of something and have to "guess or surmise." You can see how the word conjecture means that you create a theory or opinion about something without basing it in fact because the original definition of conjecture, from Old French, is "interpretation of signs and omens." Since signs and omens are pretty subjective, it makes sense that the word would then move to its current meaning. However, even though it only seems like weather reports are conjectures, they are actually based on evidence!

Keep Reading on Vocabulary.com

Vocabulary lists containing conjecture

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

It was an eye-catching conjecture: one of the most revered of the Founding Fathers subjecting people held against their will to possibly painful shocks.

From Salon ● Sep. 25, 2026

The claims amounted to “anonymous conjecture and character assassination,” he added.

From The Wall Street Journal ● Sep. 25, 2026

The rumor mill is active, locals say, and includes conjecture on whether Musk himself might show up.

From The Wall Street Journal ● Aug. 22, 2026

Schnoebelen said that while the speculating on the origins of the statue is all conjecture at this point, she does enjoy the attention the statue has brought to this particular period of art.

From Los Angeles Times ● Aug. 14, 2026

His conjecture that the orbits of the planets are circumscribed by the five platonic solids were no more supported by Tycho’s data than by Copernicus’.

From "Cosmos" by Carl Sagan

Meanwhile, conjectures about the impact of a deal or non-deal have proliferated.

From Los Angeles Times ● Sep. 16, 2026

But we have reached the point where famous math conjectures that stood for decades seem to be falling every day.

From The Wall Street Journal ● Aug. 1, 2026

"This unprecedentedly clear signal of the black hole merger known as GW250114 puts to the test some of our most important conjectures about black holes and gravitational waves," Isi said.

From Science Daily ● Dec. 8, 2025

Molly White, that indispensable and indefatigable chronicler of newfangled financial technology, conjectures that “many people who hold crypto ... probably don’t identify as crypto advocates at all.”

From Los Angeles Times ● Aug. 1, 2024

Finally out of Nanny’s talk and her own conjectures she made a sort of comfort for herself.

From "Their Eyes Were Watching God" by Zora Neale Hurston

Erdős conjectured that the maximum number of pairs, suggested by a gridlike system, could increase only slightly faster than the number of dots.

From The Wall Street Journal ● Jun. 14, 2026

But, for an elusive conjectured class of materials, physicists have now shown that the surface previously thought to be "featureless" holds an unmistakable signature that could lead to the first definitive observation.

From Science Daily ● Jan. 16, 2024

“Is there a universal basis for selection? Is there a more quantitative formalism underlying this conjectured conceptual equivalence—a formalism rooted in the transfer of information?,” they ask of the world’s disparate phenomena.

From Salon ● Oct. 22, 2023

Greene conjectured that the fires were caused by “lasers or blue beams of light...coming down to Earth I guess.”

From Los Angeles Times ● Jul. 17, 2023

If the sacrifice was not accepted, Bobby conjectured, Byrne would be lost; but if he did accept it, he’d also be lost.

From "Endgame" by Frank Brady

The outlay had some crypto followers conjecturing that he meant to consolidate the industry in his own hands.

From Los Angeles Times ● Nov. 9, 2022

"Rather than conjecturing whether Xi would restrain actions before the party congress, it is more realistic to analyse its daily military activities and make preparations accordingly," the official added.

From Reuters ● Feb. 23, 2022

We tune in for the fighting, assigning meaning to each expression, conjecturing about what happens when the cameras are off.

From Salon ● Nov. 6, 2021

Seattle needs leadership that will solve Seattle’s problems, not shameless conjecturing to tilt the playing field.

From Seattle Times ● Oct. 19, 2021

They had a pleasant five minutes conjecturing about how much was in the bank.

From "A Tree Grows in Brooklyn" by Betty Smith

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