Why is sourdough called sourdough?

Sourdough is called so because it is leavened using naturally occurring wild yeast and lactic acid bacteria, which produce lactic acid during fermentation, giving the bread its characteristic sour flavor. The term "dough" refers to the mixture of flour and water that is fermented to create the bread. This traditional method of fermentation contrasts with using commercial yeast, contributing to the unique taste and texture of sourdough bread.