From the character 谢 (xiè), meaning "to decline, to thank, or to wither." Its use as "thank you" dates to Classical Chinese, where 谢 conveyed the idea of humbly acknowledging a favor. Doubling the word (谢谢) is a common Mandarin intensification pattern that softens and warms the expression.

In mainland China, saying 谢谢 to close family members or very good friends can occasionally feel overly formal — intimacy is sometimes shown by *not* thanking effusively. However, for acquaintances, service workers, and strangers it is always appreciated and expected. In Taiwan and overseas Chinese communities, usage is generally more casual and frequent. Don't confuse with the Japanese ありがとう — both mean "thank you" but share no linguistic connection.