Understanding What Category Do Peanuts Fall Under: Legume or Nut?

November 12, 2025 •

3 min read

Despite the name, peanuts are botanically classified as legumes, placing them in the same plant family as peas, lentils, and chickpeas. This common confusion arises because of their culinary similarities to true nuts, and their distinctive underground growth pattern further distinguishes them from tree-borne nuts.

Quick Summary

This article explains the scientific classification of peanuts as legumes due to their unique growth habit and family. It contrasts this with their culinary use as nuts, detailing the nutritional similarities and important distinctions, including allergy information.

Key Points

Botanical Classification: Peanuts are legumes, members of the Fabaceae family, which includes peas and beans.
Underground Growth: Peanuts grow in pods underground via a process called geocarpy, unlike true nuts which grow on trees.
Culinary Application: In the kitchen, peanuts are used as nuts due to their similar flavor profile, texture, and nutritional content.
Nutritional Value: Peanuts are high in protein, healthy unsaturated fats, fiber, vitamins, and minerals, offering numerous health benefits.
Distinct Allergies: Peanut allergies are separate from tree nut allergies, but cross-contamination is a concern for people with either condition.
Versatile Ingredient: Peanuts are a staple in global cuisine, used for making oil, butter, sauces, snacks, and a wide array of dishes.

The Botanical Classification: Peanuts Are Legumes

Botanically, the peanut ($ extit{Arachis hypogaea}$) is a legume, belonging to the Fabaceae family, also known as the pea or bean family. This classification is based on its growth pattern and seed production. Like other legumes, peanuts grow in pods. A unique characteristic of peanuts is that their fertilized ovaries, called 'pegs', grow downwards into the soil to mature into pods, a process known as geocarpy. This distinguishes them from true nuts that develop above ground on trees.

Characteristics of a Legume

Seedpod: Seeds are contained within a pod that typically splits open.
Nitrogen-fixing: Peanut plants host bacteria that enrich the soil with nitrogen.
Growth: Although most legumes grow above ground, peanuts develop their pods underground.

The Culinary Confusion: Why We Call Them Nuts

The common confusion about peanuts being nuts comes from their culinary use and characteristics. Peanuts are used similarly to tree nuts in cooking, sharing a crunchy texture, high fat content, and savory taste. The everyday use of the word "nut" is broader than the botanical definition, and peanuts fit this culinary description. This is why they are often grouped with tree nuts in stores and recipes.

Allergy Classification

It's important to note the difference for allergy purposes. Peanut allergies are distinct from tree nut allergies. However, due to the similar severe reactions and the risk of cross-contamination during processing, individuals with tree nut allergies are sometimes advised to avoid peanuts as well. Understanding the botanical difference is key for identifying the source of an allergic reaction.

Comparison of Peanuts and True Nuts

This table highlights the main differences between peanuts (legumes) and true nuts from a botanical standpoint.


Feature	Peanuts (Legume)	True Nuts (e.g., Acorn)	Tree Nuts (e.g., Almond, Pecan)
Botanical Family	Fabaceae (Pea family)	Fagaceae	Varies (e.g., Juglandaceae for walnuts)
Growth Method	Pod matures underground via geocarpy	Fruit (nut) matures above ground on a tree	Fruit (drupe) matures above ground on a tree
Shell/Pod Type	Splits open to release seeds	Hard shell that does not naturally split open	Fleshy fruit surrounding a pit with the seed inside
Primary Edible Part	The edible seeds within the pod	The single seed inside the hard shell	The edible seed inside the woody pit

Nutritional Profile and Health Benefits

Beyond their culinary versatility, peanuts offer significant nutritional benefits. They are a good source of protein, healthy unsaturated fats, fiber, vitamins, and minerals. Due to their high oil content (about 49% of calories), they are also classified as oilseeds.

Key Nutrients in Peanuts

Protein: Supports muscle repair and growth.
Healthy Fats: Monounsaturated and polyunsaturated fats beneficial for heart health.
Vitamins: Provide B vitamins (niacin, folate) and vitamin E.
Minerals: Contain magnesium, phosphorus, and manganese.
Antioxidants: Peanut skins contain antioxidants like resveratrol.

The Extensive Culinary Uses of Peanuts

Peanuts are used extensively in global cuisine, from snacks to sauces and oils. Their rich flavor and texture make them popular in diverse dishes, particularly in Southeast Asia, Africa, and the United States.

A List of Culinary Applications

Peanut Butter: A widely consumed spread made from ground roasted peanuts.
Cooking Oil: Used for high-heat cooking due to its high smoke point.
Sauces: A key ingredient in sauces like Satay.
Snacks: Enjoyed roasted, salted, and in various snack foods.
Stews and Curries: Feature in African stews and Indian curries and rice dishes.
Baked Goods: Incorporated into cookies, cakes, and candy bars.

Conclusion

In conclusion, peanuts are botanically legumes due to their unique underground growth and plant family, but are referred to as nuts in a culinary context because of their similar taste, texture, and uses. This dual identity is a source of confusion but highlights the peanut's versatility and importance. Understanding this difference is crucial for allergy awareness and appreciating this nutritious crop. National Peanut Board

Frequently Asked Questions

Peanuts are botanically considered a fruit, specifically a type of legume. A fruit is a botanical term for the seed-bearing structure of flowering plants, and the peanut pod containing the seeds fits this definition.

The term 'nut' is used in a culinary sense, not a botanical one, to describe peanuts. They share similar characteristics with true nuts, such as a high fat content, crunchy texture, and similar culinary uses, which is why they are colloquially and culinarily referred to as nuts.

A legume is a plant whose seeds grow in a pod that typically splits open, while a true nut is a dry, hard-shelled fruit that doesn't split open on its own. A key differentiator is that peanuts (legumes) grow underground, whereas true nuts grow on trees.

No, peanuts are not related to tree nuts. Peanuts are legumes, belonging to the pea family, while almonds and walnuts are tree nuts from different plant families entirely.

A person with a tree nut allergy might not necessarily be allergic to peanuts, as they are from a different plant family. However, because of the high risk of cross-contamination in processing facilities, allergists often advise avoiding both, though this depends on the individual's specific allergy profile.

Geocarpy is the unique process where the peanut plant pushes its fertilized ovary (the 'peg') into the soil to develop and mature the peanut pod underground. The name for the species, $ extit{hypogaea}$, literally means 'under the earth'.

Yes, peanuts are highly nutritious. They are rich in protein, healthy fats, fiber, vitamins, and minerals that support heart health and aid in weight management by promoting fullness.