I remember there was always that one snotty kid in my elementary school science classes who, as we were learning about how plants grow and the difference between fruits and vegetables or whatever five- or six-year-olds learn in school, smugly told the teacher that a tomato is, in fact, a fruit, not a vegetable. Now, as an adult, I know that that annoying first-grader was right—that in the most technical sense, a tomato is a fruit, not a vegetable. But over two decades later, I still don't fully understand the difference between a fruit and a vegetable or why tomato is a fruit, even though I've planted plenty of tomatoes in my dad's garden and eaten many, many more.
So what's the difference between a fruit and a vegetable? Though conventional wisdom might make you believe that a vegetable is savory and a fruit is sweet, the distinction is actually in based in botany. As Robert Alan Lewis writes in the CRC Dictionary of Agricultural Sciences, the definition of fruit is "the ripened ovary of a flower together with any accessory parts associated with it."
What that means, in less technical terms, is the fruit of a plant is "a seed-bearing structure that develops from the ovary of a flowering plant," according to the staff of LiveScience. And by this definition, tomatoes are definitely fruits—as are "squash, pumpkins, cucumbers, peppers, eggplants, corn kernels, and bean and pea pods," writes Rebecca Rupp for National Geographic. So are avocados, nuts, and sunflower seeds.
The definition of vegetable, however, is way less specific. A vegetable is basically any part of the plant that you can eat that's not the ripened ovary. That means leaves, like lettuce; roots, like potatoes or carrots; buds, like cauliflower or broccoli; and even stalks, like celery.
At the end of the day, though, knowing the technical, botanical difference between fruits and vegetables doesn't really matter all that much. The US government actually looks to the ordinary or culinary distinction between fruits and vegetables—which is to say that the former are sweet and found more commonly in desserts, while the latter are savory and part of a main dish—to define them. That's according to a 1893 US Supreme Court decision in Nix v. Hedden, which determined that a tomato is a vegetable, even though it's technically a fruit.
If you're still getting hung up on the difference between a fruit and a vegetable, you should know that a banana is technically an herb, so don't feel bad if you feel totally confused all over again. A tomato is a vegetable if you want it to be, no matter what any first grader might try to tell you.