Simple Definition of conjecture

: an opinion or idea formed without proof or sufficient evidence
Full Definition of conjecture
1 obsolete a : interpretation of omens b : supposition
2 a : inference from defective or presumptive evidence b : a conclusion deduced by surmise or guesswork c : a proposition (as in mathematics) before it has been proved or disproved
Examples of conjecture in a sentence
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 manpower 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.
Origin of conjecture
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
Other Logic Terms
Rhymes with conjecture
Simple Definition of conjecture

: to form an opinion or idea without proof or sufficient evidence
Full Definition of conjecture
conjecturedconjecturing play \ˈjekchəriŋ, ˈjekshriŋ\
transitive verb
1 : to arrive at or deduce by surmise or guesswork : guess <scientists conjecturing that a disease is caused by a defective gene>
2 : to make conjectures (see ^{1}conjecture)as to <conjecture the meaning of a statement>
intransitive verb
: to form conjectures(see ^{1}conjecture)
Examples of conjecture in a sentence
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
Despairing of assistance and protection from below (as they foolishly conjecture) they talk of capitulating and coming upon terms with the French and Indians … —George Washington, 24 Apr. 1776, in The Papers of George Washington, 1984
Some have conjectured that the distant planet could sustain life.
We only conjecture about his motives.
Did You Know?
When the noun "conjecture" entered English in the 14th century, it referred to the act of interpreting signs or omens (as for making 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" derived via Middle English and Middle French from the Latin verb conicere ("to throw together"), a combination of "com" ("together") and "jacere" ("to throw").
Origin of conjecture
(see ^{1}conjecture)
First Known Use: 15th century
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