You’ve probably had someone gleefully tell you that a tomato was a fruit. I used to be one of those gleeful people. But then I began thinking about how to distinguish between fruits and vegetables. If a tomato is a vegetable, what about a cucumber?

I’ve heard several theories. Some say whatever comes from a flower is a fruit. Others say when you eat the plant itself and not the regenerative part it’s a vegetable. Others say that a vegetable is a root, stem or leaf, and that just about everything else is a fruit.

I did some research and found a mixed bag of nuts. (Hah!)

There was a discussion on the garden web forums, but they just went back and forth, so no definitive conclusion was reached.

The straight dope’s stated the following.

A fruit is the matured ovary of a flower, containing the seed. After fertilization takes place and the embryo (plantlet) has begun to develop, the surrounding ovule becomes the fruit. Yum. I won’t go on about the four types of fruit–simple, aggregate, multiple and accessory–which explain things like berries and pineapples.

A vegetable is considered to be edible roots, tubers, stems, leaves, fruits, seeds, flower clusters, and other softer plant parts. In common usage, however, there is no exact distinction between a vegetable and a fruit. The usual example is the tomato, which is a fruit, but is eaten as a vegetable, as are cucumbers, peppers, melons, and squashes. The classification of plants as vegetables is largely determined by custom, culture, and usage.

I was surprised to find a controversy section on the Wikipedia entry for tomato, where they explain:

Botanically speaking a tomato is the ovary, together with its seeds, of a flowering plant. This would mean that technically it would be considered a fruit. However, speaking from a culinary perspective the tomato is typically served as or part of a main course of a meal meaning that it would be considered a vegetable. This argument has lead to actual legal implications in the United States. In 1887, U.S. tariff laws which imposed a duty on vegetables but not on fruits caused the tomato’s status to become a matter of legal importance. The U.S. Supreme Court settled this controversy in 1893, declaring that the tomato is a vegetable, along with cucumbers, squashes, beans, and peas, using the popular definition which classifies vegetables in how they are used: they are generally served with dinner and not dessert. The case is known as Nix v. Hedden

In concordance with this classification, the tomato is the state vegetable of New Jersey.

Even the list of vegetables has a disclaimer stating, “Note that some herbs and vegetables which are botanically fruits are considered to be vegetables in the culinary sense.”

In the end, my conclusion is, it can be whatever you want it to be. Take your pick.