Smetana is the English-language name for the types of sour cream traditionally prevalent in Central, Eastern, and Southeastern Europe. It is a dairy product produced by souring heavy cream. It is similar to crème fraîche, but nowadays mainly sold with 9% to 42% milkfat content depending on the country. Its cooking properties are different from crème fraîche and the lighter sour creams sold in the US, which contain 12 to 16% butterfat. It is widely used in cooking and baking.

Sour cream is a dairy product obtained by fermenting regular cream with certain kinds of lactic acid bacteria. The bacterial culture, which is introduced either deliberately or naturally, sours and thickens the cream. Its name comes from the production of lactic acid by bacterial fermentation, which is called souring. Crème fraîche is one type of sour cream with a high fat content and less sour taste.