assumption
noun
as·sump·tion
ə-ˈsəm(p)-shən 
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
3
a
: 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
4
a
: the taking up of a person into heaven
b
Assumption
: August 15 observed in commemoration of the Assumption of the Virgin Mary
5
: the taking over of another's debts
6
Synonyms of assumption
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
Recent Examples on the Web
The underlying microscopic laws still allow time to flow in both directions, and entropy itself relies on assumptions about the universe’s initial conditions.
—
Prabhat Ranjan Mishra, Interesting Engineering, 25 Dec. 2025
Our mid-year innovation workshop brought this to life—bringing together colleagues from across disciplines to surface new ideas, test assumptions, and strengthen the connective tissue of our growing organization.
—Charlotte Sharpe, Big Think, 23 Dec. 2025
The authors argue that simplifying chargers—and shedding old assumptions about galvanic isolation—is the fastest path to an affordable and reliable EV-charging network, which is critical to broad EV adoption.
—IEEE Spectrum, 23 Dec. 2025
The assumption behind the lawsuit against Big Food is the usual narrative of big, bad profit-seeking food companies lying to consumers, poisoning their plates, and paying off the regulators.
—Yael Ossowski, Oc Register, 23 Dec. 2025
See All Example Sentences for assumption
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Prabhat Ranjan Mishra, Interesting Engineering, 25 Dec. 2025
Our mid-year innovation workshop brought this to life—bringing together colleagues from across disciplines to surface new ideas, test assumptions, and strengthen the connective tissue of our growing organization.
—Charlotte Sharpe, Big Think, 23 Dec. 2025
The authors argue that simplifying chargers—and shedding old assumptions about galvanic isolation—is the fastest path to an affordable and reliable EV-charging network, which is critical to broad EV adoption.
—IEEE Spectrum, 23 Dec. 2025
The assumption behind the lawsuit against Big Food is the usual narrative of big, bad profit-seeking food companies lying to consumers, poisoning their plates, and paying off the regulators.
—Yael Ossowski, Oc Register, 23 Dec. 2025
See All Example Sentences for assumption
Cite this Entry
“Assumption.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/assumption. Accessed 31 Dec. 2025.
Copy CitationKids Definition
assumption
noun
as·sump·tion
ə-ˈsəm(p)-shən
1
capitalized
: August 15 observed as a church festival to mark the taking up of the Virgin Mary into heaven
2
a
: the act of taking upon oneself or taking possession of something
3
a
: the belief that something is true
b
: a fact or statement taken for granted
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