In culinary terms, a vegetable is an edible plant or its part, intended for cooking or eating raw. In biological terms, "vegetable" designates members of the plant kingdom.
The non-biological definition of a vegetable is largely based on culinary and cultural tradition. Apart from vegetables, other main types of plant food are fruits, grains and nuts. Vegetables are most often consumed as salads or cooked in savory or salty dishes, while culinary fruits are usually sweet and used for desserts, but it is not the universal rule. Therefore, the division is somewhat arbitrary, based on cultural views. For example, some people consider mushrooms to be vegetables even though they are not biologically plants, while others consider them a separate food category; some cultures group potatoes with cereal products such as noodles or rice, while most English speakers would consider them vegetables.
Some vegetables can be consumed raw, some may be eaten cooked, and some must be cooked to destroy certain natural toxins or microbes in order to be edible, such as eggplant, unripe tomatoes, potatoes, daylily, winter melon, fiddlehead fern, and most kinds of legume/beans (such as common beans). A number of processed food items available on the market contain vegetable ingredients and can be referred to as "vegetable derived" products. These products may or may not maintain the nutritional integrity of the vegetable used to produce them.
The leek is a vegetable that belongs, along with onion and garlic, to the genusAllium, currently placed in family Amaryllidaceae, subfamily Allioideae. Historically many scientific names were used for leeks, which are now treated as cultivars of Allium ampeloprasum. Two related vegetables, elephant garlic and kurrat, are also cultivars of A. ampeloprasum, although different in their uses as food.
The edible part of the leek plant is a bundle of leaf sheaths that is sometimes erroneously called a stem or stalk.