People often mistake certain types of fruit for vegetables based on taste. A fruit that is not sweet is usually thought of as a vegetable. The difference between the two however, lies in classification, not taste buds.
A fruit is the mature ovary of a plant. Fruit, normally fleshy, contains a large seed within, such as an avocado or peach seed, or numerous tiny seeds, such as a tomato or an orange. All produce that contains seeds is botanically classified as fruit.
A vegetable is a plant's edible stem, root, tuber, leaf or flower. For example, celery, carrots, potatoes, lettuce and cauliflower are botanically classified as vegetables. Sometimes, more than one part of a plant can be consumed, such as the stem and flower of broccoli and the root and leaves of beets.
Fruit such as tomatoes, eggplant, string beans and squash are often mistaken for vegetables because they are used in savory cooking. Grocery stores and cookbooks add to the confusion by labeling and organizing produce according to culinary usage, rather than botanical classification.