Kidney beans are a type of legume, also known as rajma, that are named for their kidney-like shape and reddish-brown color. They are a nutritious food, rich in plant-based protein, fiber, vitamins, and minerals. Popular in various cuisines, they are an excellent source of nutrients like iron, folate, potassium, and magnesium, and are often used in simmered dishes because they absorb flavors well.