Young Wen San answers, with some bits I didn’t know. (The bit about yunyun”):
In addition to 等等 děngděng which the other respondents have provided, there is actually another word for etc. which features in Classical Chinese, which is 云云 yúnyún. Citations from the Hanshu and Zhuangzi:
《漢書．卷五○．汲黯傳》：「上方招文學儒者，上曰吾欲云云。」
《莊子．在宥》：「萬物云云，各復其根。」
The word 云 was the ancient form of the word “cloud”, which was eventually borrowed to mean “to say”. In order to create the distinction, the rain radical 雨 was added to 云 to form the new character for “cloud”, i.e. 雲, and this became the orthodox form moving forward, until the character simplification process in the 20th century brought 云 back as the mainstream form for “cloud”.
云云 yúnyún as the word etc. has fallen out of use in Modern Standard Chinese, perhaps partly because 云 yún itself has fallen out of use as the word for “to say”. But happily, 云云 as the word etc. still survives in the Vietnamese language, pronounced vân vân.
