Is a tomato a fruit or a vegetable?

Botanically, a fruit is the seed-bearing structure that develops from the flower's ovary, which makes tomatoes fruits without ambiguity, along with cucumbers, peppers, eggplants, squash, avocados, and beans. Vegetable is not a botanical category at all; it is a culinary one, covering edible plant parts used in savory cooking, which is why the two systems produce different answers to the same question without either being wrong.

The legal answer is its own story. In Nix v. Hedden in 1893, the Supreme Court unanimously held that tomatoes count as vegetables for tariff purposes, reasoning that ordinary usage governs commercial classification: tomatoes are served with dinner rather than dessert, so people treat them as vegetables and the tariff schedule should too. The Court explicitly acknowledged the botanical fact and set it aside as irrelevant to trade law. So the complete answer is that a tomato is a fruit botanically, a vegetable culinarily and legally in the US, and the argument only persists because people assume one classification system has to win. The genuinely surprising items are the ones that go the other way: rhubarb is a stalk used as a fruit, and strawberries are not berries botanically while bananas and avocados are.