Pumpkin refers to certain cultivars of squash, most commonly those of Cucurbita pepo, that are round, with smooth, slightly ribbed skin and deep yellow to orange coloration. The thick shell contains the seeds and pulp. Some exceptionally large cultivars of squash with similar appearance have also been derived from Cucurbita maxima.
Pumpkins are very versatile in their uses for cooking. Most parts of the pumpkin are edible, including the fleshy shell, the seeds, the leaves, and even the flowers. When ripe, the pumpkin can be boiled, baked, steamed, or roasted. It's also delicious eaten mashed and when used in soups and purees.