The confusion over classifying produce, such as the tomato, stems from using two different systems: one based on plant science and one based on cooking and flavor. The scientific, or botanical, definition focuses entirely on the part of the plant from which the food develops. Conversely, the culinary definition relies on how the food tastes and its traditional use in a meal. This difference often leads to items being categorized differently by botanists and chefs.
Botanical Definition of Fruit
Botanically, a fruit is the mature, ripened ovary of a flowering plant that encloses the seeds. This structure develops after fertilization of the flower and serves the reproductive function of seed dispersal. The primary biological purpose of the fruit is to protect the developing seeds. This definition includes many items that are not typically thought of as fruits, such as peppers, cucumbers, and squashes, because they all originate from a flower’s ovary and contain seeds.
Botanists further classify these seed-bearing structures based on how they develop from the flower. Simple fruits, like peaches or grapes, are formed from a single ovary. Aggregate fruits, such as raspberries, arise from a single flower that has multiple ovaries. Accessory fruits, like strawberries, include tissues other than the ovary in their structure.
Botanical Definition of Vegetable
The botanical definition of a vegetable is a catch-all term for any other edible part of the plant. Vegetables are considered the vegetative portions of the plant, meaning the parts not involved in sexual reproduction. These non-reproductive parts are grouped based on the specific anatomical structure of the plant that is consumed. This includes roots (carrots and radishes), stems (asparagus or celery stalks), leafy greens (spinach and lettuce), and flower parts (broccoli and cauliflower).
How We Use Them in the Kitchen
The common confusion stems from the culinary classification, which disregards botanical origin in favor of flavor and application. In the kitchen, the distinction is mainly made between sweet items, generally labeled as fruits, and savory items, traditionally called vegetables. Culinary fruits are typically consumed raw as a snack or dessert because of their higher concentration of natural sugars. Culinary vegetables possess a savory flavor profile and are usually prepared as part of a main course or side dish.
This flavor-based system leads to the misclassification of many botanically-defined fruits. Items like tomatoes, avocados, bell peppers, eggplant, and zucchini are all technically fruits because they contain seeds and develop from a flower’s ovary. However, their savory taste and use in main dishes cause them to be universally treated as vegetables. The tomato’s dual identity was legally settled in 1893 by the U.S. Supreme Court case Nix v. Hedden.
The court ruled that for the purposes of import tariffs, the tomato should be classified as a vegetable, upholding the common usage over the scientific definition. Justice Gray noted that the tomato is prepared and eaten as a vegetable, usually with dinner or in a soup, rather than as a dessert. This legal precedent solidified that, in commerce and common language, function and flavor are the determining factors. Therefore, the difference between a fruit and a vegetable ultimately depends on whether you are holding a microscope or a kitchen knife.