Potpie legume is a term used to describe a type of vegetable that is commonly used in potpies. The most common potpie legume is the PEA, which is a three-letter word. Peas are a type of legume that are small, round, and green in color. They are a popular ingredient in many dishes, including potpies, soups, and stews. Peas are high in protein and fiber, making them a nutritious addition to any meal.