buttermilk
//ˈbʌtərˌmɪlk//
Noun
1
The slightly sour liquid remaining after butter has been churned from cream.
Traditional buttermilk is the liquid left over after churning butter.
2
A cultured dairy drink made by adding lactic acid bacteria to milk, giving it a tangy flavor and thick consistency.
I like to drink buttermilk because of its tangy taste.