Why tomatoes, cucumbers, and olives are secretly fruits—not vegetables

Many foods commonly called vegetables are actually fruits in botanical terms. The confusion stems from how plants are classified in science versus how they're used in cooking. A recent look at these definitions highlights some surprising examples.

Botanists define fruits as the seed-bearing parts of a plant that develop from flowers. This means olives, pumpkins, and even eggplants qualify as fruits. Olives grow from the blossoms of olive trees, while pumpkins and squash—including zucchini—start as flowers on vines. Eggplants, despite their savoury use, are technically berries.

Green beans also fit the botanical definition. Their pods contain seeds that could sprout if planted. Similarly, okra is a fruit because its entire pod holds seeds. Cucumbers, closely related to squash, follow the same rule.

Yet legal and culinary traditions often override science. In 1893, the US Supreme Court ruled that tomatoes should be treated as vegetables for trade purposes. This decision was based on how people commonly use them, not their botanical roots. Today, tomatoes remain legally classified as vegetables in the United States, even though they grow from flowers and carry seeds.

Vegetables, by contrast, refer to other edible plant parts. These include stems, leaves, roots, and bulbs. The distinction explains why carrots and lettuce are always vegetables, while seed-filled foods like tomatoes and cucumbers blur the lines.

The divide between fruits and vegetables depends on whether you ask a scientist or a chef. Botanically, seed-bearing foods like tomatoes and cucumbers are fruits, regardless of how they're cooked. Legal rulings, such as the 1893 Supreme Court case, further complicate the matter by prioritising common usage over biology.