Is a tomato a fruit or a vegetable?
Botanically, a tomato is a fruit, because it grows from a flower and holds seeds. In the kitchen it's a vegetable, and was once legally declared one.
Going deeper
To a botanist, any seed-bearing part that grows from a flower's ovary is a fruit. That makes tomatoes, cucumbers, peppers and pumpkins all fruits.
Cooks group food by taste and use, and tomatoes go in savoury dishes. In 1893 the US Supreme Court ruled in Nix v. Hedden that tomatoes should be taxed as vegetables, since that's how people use them.