ˈthank you interjection

1. used to tell someone that you are grateful for something they have given you or done for you Synonym : thanks:
Margaret handed him the butter. ‘Thank you,’ said Samuel.
Thank you very much, Brian.
thank you for (doing) something
It’s good to see you, Mr. Mathias. Thank you for coming.
Dear Grandma, thank you for the lovely shirt you sent me for Christmas.
► Do not say ‘I thank you’.

2. used as a polite way of accepting something that someone has offered:
‘Can I give you a lift into town?’ ‘Oh, thank you.’

3. used when politely answering someone’s question:
‘How was your trip to Paris?’ ‘Very nice, thank you.’

4. no, thank you used to say politely that you do not want something:
‘Would you like some more coffee?’ ‘No, thank you, I’m fine.’

5. used at the end of a sentence when telling someone firmly that you do not want their help or advice and are slightly annoyed by it:
I can manage quite well on my own, thank you!

[TahlilGaran] Dictionary of Contemporary English ▲

ˈthank-you noun [countable]

1. something you say or do in order to thank someone:
This present’s a thank-you for helping me last week.
I just want to say a big thank-you to everyone who supported us.

2. thank-you letter/note/card a short letter etc in which you thank someone

[TahlilGaran] Dictionary of Contemporary English ▲

thank you
noun
ADJ. big, special | polite
VERB + THANK YOU give, say He didn't even say thank you. We said our thank yous and goodbyes to the hosts and went to catch a cab.
get
THANK YOU + NOUN letter, present
PREP. ~ for She got a special thank you for all her hard work.
~ to a big thank you to the hospital staff

[TahlilGaran] Collocations Dictionary ▲