The nounvegetable usually means an edible plant or part of a plant other than a sweetfruit or seed. This typically means the leaf, stem, or root of a plant.
However, the word is not scientific, and its meaning is largely based on culinary and cultural tradition. Therefore, the application of the word is somewhat arbitrary and subjective. For example, some people consider mushrooms to be vegetables even though they are not plants, while others consider them a separate food category.
Some vegetables can be consumed raw, some may be eaten cooked, and some must be cooked in order to be edible. Vegetables are most often cooked in savory or salty dishes. However, a few vegetables are often used in desserts and other sweet dishes, such as rhubarb pie and carrot cake.
As an adjective, the word vegetable is used in scientific and technical contexts with a different and much broader meaning, namely of "related to plants" in general, edible or not — as in vegetable matter, vegetable kingdom, vegetable origin, etc. The meaning of "vegetable" as "plant grown for food" was not established until the 18th century.