supposition
Americannoun
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the act of supposing
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a fact, theory, etc, that is supposed
Other Word Forms
Etymology
Origin of supposition
First recorded in 1400–50; late Middle English, from Latin suppositiōn- (stem of suppositiō ) “substitution” ( English meaning by association with suppose ), equivalent to supposit(us) (past participle of suppōnere “to substitute”) + -iōn- stem of noun suffix -io; see origin at -ion, sup-, position
Explanation
A supposition is a guess or a hypothesis. Your supposition that your kids will automatically wash their hands before dinner is probably false. You'd best remind them to do it or risk dirty hands at dinner. What's the difference between an assumption and a supposition — both nouns that are often taken as synonyms for each other? An assumption is an idea or theory that is usually made without proof. A supposition, on the other hand, has the connotation that the idea or theory is testable and provable. If you are to meet someone named Hunter, you may make the assumption that you are meeting a man. But if you know that Hunter lives in an all-female dorm, you may have the supposition that Hunter is a woman.
Vocabulary lists containing supposition
"The Tell-Tale Heart" by Edgar Allan Poe
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"The Declaration of Sentiments" (1848)
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"The Pit and the Pendulum," Vocabulary from the short story
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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.
The investor supposition was they likely wouldn’t become acquisition targets.
From Barron's • Sep. 26, 2025
There’s some supposition, including from Ourand at Puck, that the heat here stems from Disney’s secretive plan to establish a streaming-specific digital service, Venu Sports, in partnership with Warner Bros. and Fox.
From Slate • Sep. 7, 2024
You might leave the enjoyable “Sangre de Nopal/Blood of the Nopal” scratching your head over the supposition of the primacy of an art and science “collision.”
From Los Angeles Times • Aug. 29, 2024
She added the claim that Aldi's sales could only be the result of gaining unfair advantage from Thatchers' reputation "amounts to little more than supposition".
From BBC • Jan. 24, 2024
On the second supposition I put out my hand and awakened him, but the dream must have been strong.
From "Travels with Charley in Search of America" by John Steinbeck
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
