Meaning & use
assumption
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Meanings
nouncountable
A belief you take to be true and build your plans or arguments on, without having checked it.
Grammar: Usually countable: we made three assumptions, not 'much assumption'.
Patterns
- the assumption that something is true
- on the assumption that something
- make an assumption about something
The budget rests on the assumption that sales will grow by five percent.
It was a safe assumption that the train would be crowded on a holiday weekend.
Don't make assumptions about her views just because of where she grew up.
noununcountableformal
The act of taking on a role, duty or power, or of starting to hold it.
Grammar: Usually followed by of: the assumption of office, not 'an assumption office'.
Patterns
- the assumption of something
The assumption of power by the new council was peaceful.
His assumption of responsibility for the project calmed the whole team.
Her assumption of the chairperson's duties began on Monday.
Word forms
| plural | assumptions |
|---|
Common combinations
- make an assumption
- You made an assumption about the schedule without asking anyone.
- a basic assumption
- A basic assumption of the model is that prices stay stable.
- challenge an assumption
- Good scientists challenge assumptions rather than protecting them.
- on the assumption that
- We booked a small room on the assumption that few people would come.
- a false assumption
- It is a false assumption that older workers cannot learn new tools.
Synonyms and how they differ
- presumption
- Presumption suggests a belief held because it seems probable, and can also mean arrogant boldness, which assumption never does.
- premise
- A premise is a statement an argument starts from, so it is more formal and tied to logic than a general assumption.
- supposition
- A supposition is a guess you put forward, often without strong grounds, so it sounds more tentative than an assumption you act on.
Opposites
Word family
- assume verb
- to accept something as true without checking
- assumed adjective
- taken for granted, or fake, as in an assumed name
- assumptive adjective
- based on assumption (rare, formal)
Commonly confused: assumption or presumption?
assumption vs presumption
A presumption is a belief based on probability, and it can mean rude overconfidence; an assumption is just something taken as true.
Practice
We planned the picnic on the ___ that the weather would stay dry.
Choose one answer.
An assumption is something accepted without checking. Proof, conclusion and evidence all suggest the weather had already been confirmed, which does not fit the plan.
Make it your own
Write a sentence using “assumption”, then check it and compare it with the examples above.