Claim vs Thesis

When to use each in English, with meaning, register, and examples.

Claim

Top 1,000 (very common)B1verb

Thesis

FormalTop 3,000 (common)B2noun
Most formal: ThesisMost common: Claim
 ClaimThesis
Pronunciation🇬🇧 /["/kleɪm/","/kleɪmz/","/kleɪmd/","/ˈkleɪmɪŋ/"]/🇺🇸 /["/kleɪm/","/kleɪmz/","/kleɪmd/","/ˈkleɪmɪŋ/"]/🇬🇧 /["/ˈθiːsɪs/","/ˈθiːsiːz/"]/🇺🇸 /["/ˈθiːsɪs/","/ˈθiːsiːz/"]/
MeaningTo say that something is true or to assert something.A long paper that students write for their degree showing their research.
ExampleShe decided to claim her inheritance after the will was read.She spent years researching her thesis on climate change.
RegisterNeutralFormal
How commonTop 1,000 (very common)Top 3,000 (common)
CEFR levelB1B2
Part of speechverbnoun
Collocationsjustifiably, legitimately, rightfully, attempt to, try to, back, be able to, be entitled to, can, on, back, be able to, be entitled to, can, ondoctoral, honors, MA, do, work on, write, project, research, topic, in a/​the thesis, thesis about, thesis on, basic, central, fundamental, prove, support, disprove, thesis about
Antonymsdeny, revoke, rejectantithesis, counterargument
Common mistakesUsing 'claim' as a noun without context, e.g. 'I have a claim.', Confusing 'claim' with 'proclaim' when meaning to declare something publicly., Misusing 'claim' with non-specific subjects, e.g. 'He claims that he is best.'Confusing 'thesis' with 'theory' — a thesis is a specific argument or claim, while a theory is a broader system of ideas., Using 'thesis' to refer to any paper — it specifically refers to a major project typically for a graduate degree., Mispronouncing 'thesis' — make sure to pronounce it correctly as 'thee-sis'.
Usage notesUse 'claim' when stating something you believe is true. It's appropriate in discussions, debates, and legal contexts. Avoid in casual conversations where less assertive language is preferable.Used primarily in academic contexts when discussing research or formal arguments. Not appropriate in casual conversations.

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Claim

Frequently asked questions: Claim vs Thesis

What's the difference between Claim and Thesis?

Claim: To say that something is true or to assert something. Thesis: A long paper that students write for their degree showing their research.

Which is more formal: Claim and Thesis?

Thesis is the most formal of these.

Which is more common: Claim and Thesis?

Claim is the most common in everyday English.

Which is more advanced: Claim and Thesis?

Thesis is the highest level, at B2, on the CEFR scale.

Are Claim and Thesis the same CEFR level?

Claim: B1, Thesis: B2 on the CEFR scale.

What part of speech are Claim and Thesis?

Claim: verb, Thesis: noun.

Can you show an example of each?

Claim: She decided to claim her inheritance after the will was read. Thesis: She spent years researching her thesis on climate change.

Can I use Claim and Thesis interchangeably?

Not always. Claim and Thesis 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.

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