I never expected wet markets to be the talk of the day, but here we are, I guess. In case you're not familiar with the term, wet market originated in Singapore shortly after independence to differentiate fresh food markets from the new supermarkets.

They were (and are) essentially markets offering a variety of produce, meat, fish, and dry foods, and were called “wet” because the floor was constantly wet, both because of frequent hosing and because of the ice used to keep fish fresh, water used to spray down produce, etc.

The term later became popular among English speakers in HK (although the Cantonese term is street market or just market, AFAIK - please correct me if I'm wrong on that). Here is a good primer on the history of Singaporean wet markets. https://www.nhb.gov.sg/~/media/nhb/files/resources/publications/ebooks/nhb_ebook_wet_markets.pdf

It's important to note that the majority of wet markets do not sell living animals, let alone wild animals. There are certainly markets that do so in several countries, but that is a smaller & more specific category. See the explainer from @Ben_Westcott https://www.cnn.com/2020/04/14/asia/china-wet-market-coronavirus-intl-hnk/index.html

There is a lot of confusion over these categories, with a variety of who-cares celebrities calling for the closure of "wet markets." What they should be asking for is a much more rigorous policing of the wildlife trade, including in China.

Calling for the closure of "wet markets" is like asking for all farmers markets to be shut, but using orientalist language that makes it clear we are only taking about foreign and exotic places. It makes you look dumb and like a bit of a racist.