supposition

noun

sup·​po·​si·​tion ˌsə-pə-ˈzi-shən 

1

: something that is supposed : hypothesis

2

: the act of supposing

suppositional

ˌsə-pə-ˈzi-sh(ə-)nəl 

adjective

Synonyms

• hypothesis
• proposition
• theory
• thesis

Examples of supposition in a Sentence

a supposition that proved correct

This is just idle supposition.

Recent Examples on the Web

In a new interview with PEOPLE about her new memoir, This Far, Holker reacted to suppositions about the relationship between Boss and DeGeneres, after the TV personality joined the comedy icon's Ellen DeGeneres Show daytime series as its resident DJ in 2014. —EW.com, 5 Feb. 2025

The fact that the Soviets had detonated their first atomic bomb the previous summer buttressed that faulty supposition. —James Hershberg, Foreign Affairs, 24 Feb. 2022

The supposition that the crime was committed accidentally seems equally implausible. —Aja Romano, Vox, 7 Dec. 2018

There weren’t any suppositions or guesses about what somebody was thinking or feeling or looked like or anything like that. —Barbara Booth, CNBC, 26 Nov. 2024

Word History

Etymology

Middle English supposicioun, from Anglo-French supposicion, from Late Latin supposition-, suppositio, from Latin, act of placing beneath, from supponere

First Known Use

15th century, in the meaning defined at sense 1

Phrases Containing supposition

• on the supposition that

Kids Definition

supposition

noun

sup·​po·​si·​tion ˌsəp-ə-ˈzish-ən 

1

: something that is supposed

2

: the act of supposing

suppositional

-ˈzish-nəl 

-ən-ᵊl

adjective