The US Supreme Court ruled the tomato a vegetable.
Botanically, a tomato is a fruit: it grows from a flower and holds seeds. But in 1893, in Nix v. Hedden, the US Supreme Court ruled it a vegetable for tax purposes, because that's how people cook and eat it. The case was about import duty, not botany.
Tomatoes originated in western South America and were domesticated in Mesoamerica. When they reached Europe in the 16th century, they were met with suspicion in some places. They belong to the nightshade family, which includes poisonous plants such as deadly nightshade, and for a long time many people grew them as ornamental curiosities rather than food.
By the late 19th century, tomatoes were widely eaten in the United States, and they became the subject of an unusual legal case. The Tariff Act of 1883 imposed a duty on imported vegetables but not on fruit. The Nix family, who imported tomatoes into New York, sued the customs collector Edward Hedden to recover the duties they had paid, arguing that tomatoes were botanically fruit.
In 1893, the Supreme Court ruled unanimously against them. Justice Horace Gray acknowledged that, botanically, tomatoes are the fruit of a vine. But in the common language of the people, he wrote, they are vegetables: usually served at dinner with the main part of the meal, not as dessert, like fruit. Since tariff laws use words in their ordinary meaning, the tomato was a vegetable.
The case is still cited in discussions of how the law interprets everyday language. Botanically, many 'vegetables' are fruits: cucumbers, courgettes, peppers and aubergines all develop from flowers and carry seeds. For the gardener, the distinction doesn't matter much. Tomatoes like warmth, sun and steady watering, whatever you call them.
Source: Wikipedia — Nix v. Hedden · Text summarised from Wikipedia (CC BY-SA 4.0)
