Longman Dictionary of Contemporary English
thank-you
noun
COLLOCATIONS FROM OTHER ENTRIES
a thank-you letter
▪ Mum made me write thank-you letters for all my birthday presents.
EXAMPLES FROM OTHER ENTRIES
▪ She baked them a dozen cookies as a thank-you.
EXAMPLES FROM CORPUS
▪ Anna's first kiss is a thank-you for the warmth William exudes in spite of his nervousness.
▪ Herndon says she does not need a thank-you in return.
▪ The party was meant to have been a thank-you to the casino staff from the management.
Wiktionary
thank-you
n. 1 An expression of gratitude. 2 (''as a modifier before a noun'') That expresses thanks.
Usage examples of "thank-you".
Good^byes and thank-yous were exchanged, but it was an awkward moment for Anakin.
I said, and did as she'd asked After the hellos and thank-yous, I went on, "You told me you wanted to get involved in the new technology.
And everywhere they went, there were thank-yous and God-bless-yous when they left.
A moment or two later, shrieks and thank-yous came tumbling down from upstairs.