Cool MateAssumption vs Hypothesis
When to use each in English, with meaning, register, and examples.
Assumption
Top 2,000 (common)B2noun
Hypothesis
FormalTop 3,000 (common)B2noun
Most formal: HypothesisMost common: Assumption
| Assumption | Hypothesis | |
|---|---|---|
| Pronunciation | 🇬🇧 /["/əˈsʌmpʃn/"]/🇺🇸 /["/əˈsʌmpʃn/"]/ | 🇬🇧 /["/haɪˈpɒθəsɪs/","/haɪˈpɒθəsiːz/"]/🇺🇸 /["/haɪˈpɑːθəsɪs/","/haɪˈpɑːθəsiːz/"]/ |
| Meaning | Something you think is true without proof. | An idea or guess that can be tested. |
| Example | Her assumption that everyone would agree was proven wrong. | The hypothesis proposed by the scientists was groundbreaking in its implications. |
| Register | Neutral | Formal |
| How common | Top 2,000 (common) | Top 3,000 (common) |
| CEFR level | B2 | B2 |
| Part of speech | noun | noun |
| Collocations | basic, fundamental, key, number, series, set, make, base something on, start from, underlie something, underpin something, on the assumption that, assumption about | plausible, bold, speculative, construct, develop, form, concern something, be based on something, predict something, on a/the hypothesis, hypothesis about, hypothesis concerning |
| Antonyms | fact, certainty, truth | fact, certainty, truth |
| Common mistakes | Confusing 'assumption' with 'presumption', which has slightly different legal meanings., Using it without a specific subject ('the assumption of...'), Mispronouncing it as 'assumpt-tion' instead of 'assump-tion'. | Confused with 'theory' - a hypothesis is not proven yet., Sometimes used as a verb, but it's only a noun., Plural is often mistakenly written as 'hypothesises' instead of 'hypotheses'. |
| Usage notes | Use 'assumption' when discussing beliefs or ideas that are taken for granted. It is appropriate in both written and spoken contexts, especially in discussions related to reasoning or theories. Avoid using it in very casual conversations. | Used mainly in academic and scientific contexts. Avoid using it in everyday conversation as it's too technical for casual discussions. |
Frequently asked questions: Assumption vs Hypothesis
What's the difference between Assumption and Hypothesis?
Assumption: Something you think is true without proof. Hypothesis: An idea or guess that can be tested.
Which is more formal: Assumption and Hypothesis?
Hypothesis is the most formal of these.
Which is more common: Assumption and Hypothesis?
Assumption is the most common in everyday English.
Are Assumption and Hypothesis the same CEFR level?
Assumption: B2, Hypothesis: B2 on the CEFR scale.
Can I use Assumption and Hypothesis interchangeably?
Not always. Assumption and Hypothesis are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.