Curds are a dairy product obtained by curdling (coagulating) milk with rennet or an edible acidic substance such as lemon juice or vinegar and then draining off the liquid portion (called whey). Milk that has been left to sour (raw milk alone or pasteurized milk with added lactic acid bacteria or yeast) will also naturally produce curds, and sour milk cheese is produced this way.
In India, the word curd is frequently used to mean yoghurt. In South India, it is common practice to finish any meal with curd or buttermilk. In Sweden, curds is a major ingredient of the traditional baked cheesecakes Ostkaka (with egg, flour, almonds), which is eaten with jam and cream.