as·​sump·​tion | \ ə-ˈsəm(p)-shən How to pronounce assumption (audio) \

Definition of assumption

1 : a taking to or upon oneself the assumption of a new position
2 : the act of laying claim to or taking possession of something the assumption of power
3a : an assuming that something is true a mistaken assumption
b : a fact or statement (such as a proposition, axiom (see axiom sense 2), postulate, or notion) taken for granted
4a : the taking up of a person into heaven
b capitalized : August 15 observed in commemoration of the Assumption of the Virgin Mary
5 : the taking over of another's debts

Keep scrolling for more

Examples of assumption in a Sentence

I made the assumption that he was coming, so I was surprised when he didn't show up. He will come home tomorrow. At least, that's my assumption. Many scientific assumptions about Mars were wrong. I'm telling you our arrival time on the assumption that you will check to see whether or not our flight is on time before you come to the airport. Her plan is based on the underlying assumption that the economy will improve in the near future. her assumption of the presidency the buyer's assumption of debt
See More
Recent Examples on the Web An antibody test in April proved that assumption false. Bill Addison, Los Angeles Times, "Are you ready to eat in an L.A. restaurant tonight?," 30 May 2020 Don’t let planning lead to assumptions about the future. Doug Lesmerises, cleveland, "Why an Ohio State football season looks ready to happen, with one looming question," 27 May 2020 Above all, many influential voices across the ideological spectrum are united in the assumption that the most important subject — constant and all-consuming — to be thinking and talking about is Trump. TheWeek, "Has Trump successfully politicized the pandemic?," 22 May 2020 Now, there's potential to flip longstanding assumptions about where the tech hubs really should be, with potential consequences for the culture and real estate values of markets like San Francisco. Brian Fung, CNN, "Silicon Valley defined modern office culture. Now it needs to learn to live without it," 22 May 2020 Kirra Backstrap Sandal People often associate orthotic footwear with frumpy, oversized sneakers—but this sleek pair proves that assumption wrong., "You Can Already Score Vionic Sandals on Sale Ahead of Memorial Day—Here’s Our Top 8 Picks," 19 May 2020 First-quarter earnings reports showed lenders made very different assumptions on how the economy will fare this year when setting aside funds for doubtful loans. Nicholas Comfort,, "Europe’s Bank Watchdogs Put Further Relief on Hold Until October," 19 May 2020 In recent first-quarter results, lenders used widely differing approaches and assumptions about the coming months to estimate loan losses. Rochelle Toplensky, WSJ, "Banks Are Only as Sound as Their Models," 14 May 2020 Norms—the rules and assumptions underlying interactions among individual citizens, and between citizens and the state—are the oil in the engine of a nation. Tom Mctague, The Atlantic, "We Are Stronger Than We Think," 14 May 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'assumption.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of assumption

13th century, in the meaning defined at sense 4a

History and Etymology for assumption

Middle English, from Late Latin assumption-, assumptio taking up, from Latin assumere — see assume

Keep scrolling for more

Learn More about assumption

Time Traveler for assumption

Time Traveler

The first known use of assumption was in the 13th century

See more words from the same century

Statistics for assumption

Last Updated

2 Jun 2020

Cite this Entry

“Assumption.” Dictionary, Merriam-Webster, Accessed 3 Jun. 2020.

Keep scrolling for more

More Definitions for assumption


How to pronounce assumption (audio)

English Language Learners Definition of assumption

: something that is believed to be true or probably true but that is not known to be true : something that is assumed
: the act of beginning a role, duty, etc.
: the act of taking or beginning to have power, control, etc., in a job or situation


as·​sump·​tion | \ ə-ˈsəmp-shən How to pronounce assumption (audio) \

Kids Definition of assumption

1 : the act of taking on the assumption of power
2 : something accepted as true I'm making plans on the assumption that you will be here.

Keep scrolling for more

Comments on assumption

What made you want to look up assumption? Please tell us where you read or heard it (including the quote, if possible).


See Definitions and Examples »

Get Word of the Day daily email!

Test Your Vocabulary

May 2020 Words of the Day Quiz

  • a blooming wisteria tree
  • Which is a synonym of exiguous?
Spell It

Can you spell these 10 commonly misspelled words?


Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!