On May 10, 1893, the US Supreme Court ruled in Nex v. Hedden that a tomato was classified as a vegetable for the purposes of the Tariff Act of 1883, which taxed vegetables, but not fruits.
Though technically a fruit (the court acknowledged its botanical classification as that of fruit, but argued that its common usage would make it a vegetable), the tomato is related to the potato and eggplant. Though it has been around for a long time, its purpose as human food is relatively new, as it used to have more decorative uses as “the love apple.” Some even believed the tomato to be poisonous (though to be fair, the fruit is the only part of the tomato plant that isn’t toxic). Within the last century, however, the tomato has become quite popular, and now ranks third among US vegetable crops.
To read more about this vegetable/fruit, head over to the Tomato Topic Page in Credo Reference Online!