A pumpkin is an orange gourd (Cucurbitaceae) growing from a trailing vine, commonly used in pies or in carving Jack o'lanterns for use as part of Halloween celebrations.

A pumpkin is the fruit of the gourd Cucurbita Pepo, well-known in English cottage gardens, and largely cultivated in continental Europe and North America.

The pumpkin varies much in form, being sometimes nearly globular, but more generally oblong or ovoid in shape; the rind is smooth and very variable in colour.

It is a useful plant to the American backwoods farmer, yielding, both in the ripe and unripe condition, a valuable fodder for his cattle and pigs, being frequently planted at intervals among the maize that constitutes his chief crop. The larger kinds acquire a weight of 40 to 80 lb (18 to 36 kg) but smaller varieties are in more esteem for garden culture. When ripe, the pumpkin is boiled or baked, or made into various kinds of pie, alone or mixed with other fruit; while small and green it may be eaten like the vegetable marrow. The name squash is applied in America to this and other species of the genus Cucurbita. The name is adapted from an American Indian word (see L. H. Bailey, Cyclopaedia of American Horticulture, where is a fuller account of the squashes).

Summer squashes are mostly varieties of Cucurbita pepo; winter squashes are either C. maxima or C. moschata. The varieties of pumpkins and squashes are numerous and great variety in size and shape; it is difficult to keep them pure if various kinds are grown together, but the true squash (C. maxima) do not hybridize with the true pumpkin species If carefully handled to avoid cracking of the skin, and kept dry and fairly warm, winter squashes may be kept for months.

Pumpkins have historically been pollinated by the native squash bee Peponapis pruinosa, but this bee has declined, probably due to pesticide sensitivity, and most commercial plantings are pollinated by honeybees today. One hive per acre is recommended by the US Department of Agriculture. Gardeners with a shortage of bees often have to hand pollinate. Inadequately pollinated pumpkins usually start growing but abort before full development. Often there is an opportunistic fungus that the gardener blames for the abortion, but the fix proves to be better pollination not fungicide.

Pumpkins are grown today in the US more for decoration than for food, and popular contests lead growers to vie for a new world record for the largest pumpkin grown. Growers have many techniques, some kept secret, but often include picking off all but one pumpkin, hand pollination, and injection of fertilizer or even milk directly into the vines with a hypodermic needle.

The largest pumpkin ever grown was grown from seeds of the Dill's Atlantic Giant variety. It was 1,458 lbs and grown by Bruce Whittier from Henniker, NH.