Is an Onion a Fruit or Vegetable?

  • By: SFUAA
  • Date: April 18, 2022
  • Time to read: 5 min.

Not so long ago, the hot question in the produce world was: Are tomatoes fruits or vegetables? Now, that debate has been solved (fruit), so we turn our attention to another item hanging out in the same section of the grocery store: the onion. 

An onion is a vegetable. More specifically, onions are root vegetables, much like beets or turnips. Because the onion bulb is the edible portion of a plant, it is classified as a vegetable.

So, you might be thinking – aren’t fruits edible portions of a plant as well? I mean, we eat them, so how does this fact distinguish onions from fruit? Read on to learn the answers to all of these questions. 

Breaking Down What Makes Up a Vegetable

When defining a word like vegetable, context is critical. When looking at a vegetable in the scientific sense, you get a broader umbrella to capture plants. When you shrink that context to what is considered a vegetable in a dining or grocery capacity, the definition gets more exact.

Vegetables, Scientifically

Merriam-Webster defines vegetables as “any of a kingdom of multicellular eukaryotic mostly photosynthetic organisms typically lacking locomotive movement or obvious nervous or sensory organs and possessing cellulose cell walls.” 

Those are a lot of scientific words for something that’s alive but can’t do many things we associate with being alive. This includes having the organs to make decisions or the ability to move around freely. 

In this capacity, an onion falls into the vegetable category. However, this category is so broad that a tomato, a strawberry, a peanut, and any other edible item from a plant would also be considered a vegetable. Sort of like the quandary, “all squares are rectangles, but not all rectangles are squares.” 

As the Vegetable Research & Information Center of UC Davis explains, fruit is produced after the maturation of the ovary. The ovary will enlarge, and the other parts of the plant will decrease. This ovary becomes the fruit that we eat. Vegetables make up the remainder of the edible portion of the plant. 

In other words, a vegetable is any edible portion of a plant that is not used for reproduction. 

Vegetables, Culinary

Some scientific laws don’t necessarily apply in the kitchen, though. As LiveScience shares, in 1893, the Supreme Court decided to tax tomatoes as a vegetable instead of fruit. They agreed because that is tomatoes’ designation in the kitchen, even though they’re scientifically classified as fruits. 

Tomatoes weren’t the only fruits classified as “vegetables” in the kitchen (and for tax purposes). Many other savory fruits, including peppers and squash, are technically fruits. This is because we eat the part of the plant in charge of reproduction. However, in the kitchen and grocery store aisle, they’re vegetables. 

Business Insider states that fourteen vegetables are scientifically fruit but treated as vegetables.

7 Varieties of Onions

There are lots of ways to classify different types of onions. In this article, we’ll separate onions into seven different varieties.

  • Green Onions 
  • Leeks 
  • Red Onions 
  • Shallots 
  • Sweet Onions 
  • White Onions 
  • Yellow Onions 

Green Onions

Green onions, also known as scallions, are commonly used as garnishes for dishes. They are not fully matured as they have not formed a bulb. The entire green onion plant is used for cooking, from the white bottoms to the green tops. 


Leeks can be their own dish. The leak is an underutilized onion variety, commonly served as a soup or covered in breadcrumbs and cheese. Leeks look like a large version of green onions and are generally considered a milder alternative. While you can eat an entire leek, typically, the dark green parts are discarded. 

Red Onions

Red onions are distinctive thanks to their reddish-purple color and bulbous form. Red onions are a more flavorful onion that can even be labeled as “spicy.” They are the most popular onion for grilling or topping a burger. They can also be pickled. 


Shallots add flavor to dishes and are red onions’ smaller cousins. They’re milder in flavor and may even have a garlicky note. 

Shallots grow in clusters – similarly to how garlic grows – whereas a traditional onion grows independently. 

Sweet Onions

Sweet onions’ most famous variety is likely the Vidalia. They are commonly found in French onion soup and are known for their sweeter taste. Sweet onions are the best when it comes to frying onions, so they’re an excellent choice for a plate of onion rings. 

White Onions

White onions are another variety that can be called spicy. They make great additions to stir-frys and salsas. These onions have the crunchiest bite. The white onions don’t handle cooking, and some of the other varieties can fall apart. 

Yellow Onions

Yellow onions are perfect substitutions for red or white onions if you’re looking for something with a milder taste. They work great in almost all cooked dishes that call for onions. The longer you leave them in the heat, the sweeter they will become. 

One thing all of these onions have in common: They’re all root vegetables. 

Root Vegetables, Explained

We’ve already established that the portion of the onion that we eat is not involved in the reproduction process of the plant. That makes the onion a vegetable scientifically. We also know that due to the more savory flavor of the onion and its position in the produce section, we classify onion as a vegetable in the culinary world. 

However, we can go deeper. An onion is a root vegetable. 

A root vegetable’s definition is right in its name. As Southern Living describes, root vegetables come from the roots or bulbous growths on the roots themselves. They do not come from the leaves or blooms of the plant. 

Root vegetables make up the starches on your plate like potatoes or yams. Most can usually fulfill your daily carb needs. However, not all root vegetables are created equal. Some root vegetables, like carrots or onions, contain few carbs at all. 


Some people may think of classifying onions as fruits because their bulbs reproduce asexually. However, in both scientific and culinary definitions, an onion is a vegetable. Although, onion flavor enhances a fruit salad with the proper ratios. What is your favorite use for an onion?


Previous Post

Are Apples Fruits or Vegetables?

Next Post

Is Broccoli Man-Made? Fact or Fiction