A peanut is a plant that grows pods containing seeds that are also known as peanuts. You may think of peanuts as nuts, but they're actually legumes.
Despite the deceptive name peanut, this plant is more closely related to peas than it is to almonds and hazelnuts. Peanuts are an important food crop around the world, in the form of oil, flour, peanut butter, and roasted, whole peanuts. Peanuts were originally called "ground nuts," and despite their popularity, they're also known for being inexpensive — thus peanuts also informally means "a very small amount of money."