The question as to whether something is a fruit or vegetable does not always have a clear-cut answer. Although the definition of a fruit is very precise from a botanical standpoint, consumer perception and even the law does not always support botanical facts or the dictionary definitions. Because of this, you always have to determine the context when determining if something is a fruit or a vegetable.
Find out what part of the plant it came from. From a botanical standpoint, vegetables are derived from the vegetative part of a plant, such as the root, stems or leaves. Fruits are derived from the ovary of a plant.
Look for seeds. Since the ovary of a plant generally contains its seeds, foods that have seeds are considered fruits from a botanical standpoint. This includes tomatoes, eggplant, cucumbers and even green beans.
Taste it. If the item is sweet, most consumers will conclude it is a fruit and not a vegetable, even if botanists do not agree.
Think about whether people typically eat it as part of a main dish or a snack. Consumers typically eat vegetables as part of a meal, but eat fruits as a snack or dessert.
Check the law. In 1893, the U.S. Supreme Court ruled that tomatoes should be legally classified as a vegetable in the United States for tax purposes, despite the botanical fact that it is actually a vegetable. Justice Horace Gray stated that he based his ruling on "common speech" and the common perception the public held about the tomato being a vegetable.