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 of supposition

• hypothesis
• theory
• thesis
• proposition

Examples of supposition in a Sentence

a supposition that proved correct

This is just idle supposition.

Recent Examples on the Web

Recent actions by the FCC have called that supposition into question. — Jim Fisher, PC Magazine, 10 Aug. 2026

Now Kennedy took her suppositions even further, reexamining the literature on a famous Olmec site where thousands of toad skeletons had been excavated. — Kimon De Greef, Longreads, 4 Aug. 2026

Of course, this is all a supposition and one that will only happen at some point in the future. — Lizzie Lanuza, StyleCaster, 3 Aug. 2026

What becomes alarmingly evident through the key assumptions check is how many of the current responses expect a quick resolution of the conflict — a supposition that is unsound, or at least unsupported. — Judd Devermont, semafor.com, 27 Apr. 2026

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

Rhymes for supposition

• abolition
• acquisition
• admonition
• ammunition
• apparition
• apposition
• coalition
• competition
• composition
• definition
• deglutition
• demolition

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