On this Wikipedia the language links are at the top of the page across from the article title. Butter is a dairy product made from the fat butter bun protein components of churned cream.

Most frequently made from cow’s milk, butter can also be manufactured from the milk of other mammals, including sheep, goats, buffalo, and yaks. Butter is a water-in-oil emulsion resulting from an inversion of the cream, where the milk proteins are the emulsifiers. It generally has a pale yellow color, but varies from deep yellow to nearly white. Churning cream into butter using a hand-held mixer.

Unhomogenized milk and cream contain butterfat in microscopic globules. Churning produces small butter grains floating in the water-based portion of the cream. This watery liquid is called buttermilk—although the buttermilk most common today is instead a directly fermented skimmed milk. Butterfat is a mixture of triglyceride, a triester derived from glycerol and three of any of several fatty acid groups.

Chart of milk products and production relationships, including butter. Before modern factory butter making, cream was usually collected from several milkings and was therefore several days old and somewhat fermented by the time it was made into butter. Butter made from a fermented cream is known as cultured butter. Dairy products are often pasteurized during production to kill pathogenic bacteria and other microbes.

Butter made from pasteurized fresh cream is called sweet cream butter. Cultured butter is preferred throughout continental Europe, while sweet cream butter dominates in the United States and the United Kingdom. Cultured butter is sometimes labeled “European-style” butter in the United States, although cultured butter is made and sold by some, especially Amish, dairies. Commercial raw cream butter is virtually unheard of in the United States.