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

capitalized : August 15 observed in commemoration of the Assumption of the Virgin Mary

5

: the taking over of another's debts

6

: arrogance, pretension

Synonyms

• given
• hypothetical
• if
• postulate
• premise
• premiss
• presumption
• presupposition
• supposition

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

Have the conversations now so that no one has assumptions or expectations and your sister-in-law is able to proactively make a plan and ask for help when needed. —R. Eric Thomas, The Mercury News, 14 Aug. 2024

For his self-tape, Feuerstein donned a leopard-print onesie (from his sole trip to Burning Man), prepared some lines of powdered sugar on a plate, and translated half his speech into Spanish under the assumption that Burton would speak the language to his Latin staff. —Mark Peikert, IndieWire, 10 Aug. 2024

The final environmental impact statement from 1986 was based on the assumption that the mine would not reach below the water table and, therefore, would remain dry. —Trilce Estrada Olvera, The Arizona Republic, 16 Aug. 2024

According to the Committee for a Responsible Federal Budget's estimates, the increase to the federal deficit would vary between Trump's and Harris' plans based on the assumption that the Republican front runner's policy would eliminate income and payroll taxes on tips. —Maya Marchel Hoff, USA TODAY, 14 Aug. 2024

Word History

Etymology

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

First Known Use

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

Phrases Containing assumption

• on/under/with the assumption
• self-assumption

Kids 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