An expression of gratitude or politeness, in response to something done or given. (interjection)
A specific expression of gratitude. (noun)
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Use "thank you" in a sentence
"Megan McKeever, thank you for always returning my emails with a “?” in the subject line."
"To Lauren McKenna, a real-live working editor, thank you for giving me the opportunity to write for you, and big hugs for making the revision process so easy."
"As is now customary this week, the prince tried a few words in the native language - dene, this time, not French: "Maihsi-cho, kay-ya-muck-puck," which roughly translated apparently means thank you very much."