A pumpkin is a gourd

Gourd

A gourd is a plant of the family Cucurbitaceae. Gourd is occasionally used to describe crops like cucumbers, squash, luffas, and melons. The term 'gourd' however, can more specifically, refer to the plants of the two Cucurbitaceae genera Lagenaria and Cucurbita or also to their hollow dried out shell...

-like squash of the genus Cucurbita

Cucurbita

Cucurbita is a genus in the gourd family Cucurbitaceae first cultivated in Mesoamerica and now used in many parts of the world. It includes species grown for their fruit and edible seeds , as well as some species grown only as gourds...

and the family Cucurbitaceae

Cucurbitaceae

The plant family Cucurbitaceae consists of various squashes, melons, and gourds, including crops such as cucumber, pumpkins, luffas, and watermelons...

 (which also includes gourds). It commonly refers to cultivar

Cultivar

A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...

s of any one of the species Cucurbita pepo

Cucurbita pepo

The species Cucurbita pepo is a cultivated plant of the genus Cucurbita. It includes varieties of squash, gourd, and pumpkin.*Acorn squash*Delicata squash*Dodi marrow, grown in South Asia*Gem squash*Heart of gold squash*Pattypan squash...

, Cucurbita mixta

Cucurbita mixta

Cucurbita mixta aka pipian is a species of squash, sometimes known as the cushaw pumpkin. C. mixta is one of the common varieties of pumpkin cultivated in the United States. The plant's adaptation to warm climates and resistance to squash borers make it very competitive in the agricultural industry...

, Cucurbita maxima

Cucurbita maxima

Cucurbita maxima, one of at least five species of cultivated squash, is one of the most diverse domesticated species, perhaps with more cultivated forms than any other crop. This species originated in South America from the wild C. maxima ssp. andreana over 4000 years ago...

, and Cucurbita moschata

Cucurbita moschata

Cucurbita moschata is a species originating in either Central America or northern South America. It includes varieties of squash and pumpkin. C. moschata varieties are generally more tolerant of hot, humid weather than C. maxima or C. pepo. They also generally display a greater...

, and is native to North America. They typically have a thick, orange or yellow shell, creased from the stem to the bottom, containing the seeds and pulp.

In Australian English

Australian English

Australian English is the name given to the group of dialects spoken in Australia that form a major variety of the English language....

, the name 'pumpkin' generally refers to the broader category called winter squash

Winter squash

Winter squash is a summer-growing annual vegetable, representing several species within the genus Cucurbita. It differs from summer squash in that it is harvested and eaten in the mature fruit stage, when the seeds within have matured fully and the skin has hardened into a tough rind. At this...

 in North America.
The word pumpkin originates from the word pepon (πέπων), which is Greek for “large melon".