Tomatoes are vegetables because they're used in savory cooking, not sweet applications.
Botanically, tomatoes are fruits, specifically berries containing seeds. The culinary distinction between fruits and vegetables is different from the botanical one. The US Supreme Court even ruled on this in 1893, confirming tomatoes are fruits botanically but acknowledging their vegetable classification in common usage.
Reception
Sources
- Tomato - Wikipedia PRIMARY
- Snopes: Tomato Fruit Vegetable REFERENCE