Any vegetable or 100% vegetable juice counts as a member of the vegetable group. Vegetables may be raw or cooked; fresh, frozen, canned, or dried/dehydrated; and may be whole, cut-up, or mashed.

Vegetables are organized into 5 subgroups, based on their nutrient content.

Some commonly eaten vegetables in each subgroup are:
 

Some vegetables can be consumed raw, and some may (or must) be cooked in various ways, most often in non-sweet (savory or salty) dishes. However, a few vegetables are often used in desserts and other sweet dishes, such as rhubarb pies and carrot cakes.

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.