upon the supposition or premise that; in the event that.

Origin of supposing

First recorded in 1835–45; see origin at suppose, -ing2
Related formsnon·sup·pos·ing, adjective



verb (used with object), sup·posed, sup·pos·ing.

to assume (something), as for the sake of argument or as part of a proposition or theory: Suppose the distance to be one mile.
to consider (something) as a possibility suggested or an idea or plan proposed: Suppose we wait until tomorrow.
to believe or assume as true; take for granted: It is supposed that his death was an accident.
to think or hold as an opinion: What do you suppose he will do?
to require logically; imply; presuppose: The evidence supposes his presence near the scene.
(used in the passive) to expect or design; require or permit (followed by an infinitive verb): The machine is supposed to make noise. I'm not supposed to run fast.

verb (used without object), sup·posed, sup·pos·ing.

to assume something; presume; think.

Origin of suppose

1275–1325; Middle English supposen < Old French supposer, equivalent to sup- sup- + poser to pose1; compare Medieval Latin suppōnere to suppose, Latin: to substitute, place below
Related formssup·pos·a·ble, adjectivesup·pos·a·bly, adverbsup·pos·er, nounmis·sup·pose, verb, mis·sup·posed, mis·sup·pos·ing.un·sup·pos·a·ble, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for supposing

presuming, assuming

Examples from the Web for supposing

Contemporary Examples of supposing

Historical Examples of supposing

  • Supposing him ready to separate from her, could she be detached from him?


    Thomas Wentworth Higginson

  • Supposing—— It was cruel to excite and upset her just for that; it made the pain worse.

  • The great mistake I made was, in supposing I had undergone any real change of heart.

    Ned Myers

    James Fenimore Cooper

  • Future obedience, supposing it perfect, could not expiate past offences.

  • Supposing she had been the stranger's sister, she was taken into his house.

British Dictionary definitions for supposing


verb (tr; may take a clause as object)

to presume (something) to be true without certain knowledgeI suppose he meant to kill her
to consider as a possible suggestion for the sake of discussion, elucidation, etc; postulatesuppose that he wins the election
(of theories, propositions, etc) to imply the inference or assumption (of)your policy supposes full employment
Derived Formssupposable, adjectivesupposer, noun

Word Origin for suppose

C14: from Old French supposer, from Medieval Latin suppōnere, from Latin: to substitute, from sub- + pōnere to put
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

Word Origin and History for supposing



early 14c., "to assume as the basis of argument," from Old French supposer "to assume," probably a replacement of *suppondre (influenced by Old French poser "put, place"), from Latin supponere "put or place under," from sub "under" + ponere "put, place" (see position). Meaning "to admit as possible, to believe to be true" is from 1520s.

Online Etymology Dictionary, © 2010 Douglas Harper

Idioms and Phrases with supposing


see I suppose so.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.