fruit v. vegetable

Fruits and vegetables may be defined by either botanical or culinary criteria.

Botanical

Fruit: the ripened ovary of a plant, containing the seeds.

Vegetable: any edible part of an herbaceous plant. This may include leaves, roots, seeds, stems, tubers, flowers, or bulbs. In this sense, edible fruits can be considered a subset of vegetables.

Culinary

A face-shaped watermelon. Image courtesy of PingMag.jp. Fruit: any sweet, edible part of a plant.

Vegetable: any savory, edible part of a plant. 

By both the botanical and culinary definitions, apples, plums, peaches, and blueberries are fruits. Botanically, however, so are tomatoes, bell peppers, black pepper, pumpkins, avocados, zucchini, pea pods, nuts, some cereals, and poisonous berries.

Examples of non-fruit vegetables are broccoli, potatoes, garlic, carrots, spinach, asparagus, and celery.

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Wikipedia on fruit v. vegetable