Peanuts (Arachis hypogaea) or “groundnuts” as they are commonly referred to, belong to the bean and legume family. Unlike tree nuts that grow above the ground, peanuts grow below the ground which makes them more closely related to legumes, such as peas and lentils. Although peanuts are technically considered a legumes, their nutritional composition is more similar to a tree nut, such as an almond, cashew, or walnut.

Source: Grains & Legumes Nutrition Council