Is it thank you, thankyou or thank-you?

If you look out for this phrase, you will see it written in all manner of ways, in various documents.

It would be nice to know which is right and wrong – and why.

We use three forms in British English – one is the verb (doing word), while the others are the noun (thing) and adjective (describing word).

Thank you

This is the verb ‘to thank’, with a direct object ‘you’.

In fact, you will know that this is two separate words, if you use the full sentence which is hidden underneath – ‘I thank you.’

From this comes the shortened version which we hear daily – ‘thank you’. It is always two words because it is the contracted version of – ‘I thank you.’


  • Thank you for coming today to this talk on written communications.
  • Thank you for your letter of 28 October 2020.


This is the noun ‘a/the thankyou’.

  • He gave a great big thankyou to all concerned.
  • There were thankyous all around as the conference ended.


This is also the spelling for the adjective, describing something (a noun) to follow.

  • He gave a thankyou card to his mother.
  • The thankyou speech was so moving.

So, why do we see ‘thank-you’ written?

If you look here, you will see how two-part verbs change to serve as nouns also, often going through the etymological change over several years.

progression word form example
Step 1 They are verbs I thank you
Step 2 They become hyphenated compound nouns A thank-you
Step 3 They become closed nouns A thankyou

So, some dictionaries are still using the ‘thank-you’ form, while others show the more inevitable ‘thankyou’ form for the noun.