A sifter is a kitchen tool used to separate and break up clumps in dry ingredients like flour, sugar, or cocoa powder. It typically consists of a mesh screen or perforated surface that allows fine particles to pass through while retaining larger pieces. This process helps to aerate the ingredients, making them lighter and easier to mix. Sifters come in various designs, including hand-held models and those that are built into mixing bowls. They are often used in baking to ensure a smooth texture in recipes, contributing to the quality of baked goods like cakes and pastries.