Zucchini is a common garden vegetable and a type of summer squash that is usually harvested while its fruit is still immature. Botanically, it is a cultivar of Cucurbita pepo, the species that also includes several other squash varieties.
The “summer” in summer squash refers to the harvesting stage: zucchini is picked while its seeds are soft and its skin is tender and edible. Gardeners commonly harvest it at roughly 15–25 centimeters long, although it can grow close to a meter if left on the plant. Oversized fruits become more fibrous, with harder skin and larger seeds.
Zucchini varieties were developed in northern Italy during the 19th century, centuries after squash reached Europe from the Americas. The first known description using the name zucchini appeared in a Milan publication in 1901. In Britain and several other countries, the same vegetable is generally called courgette. A common mix-up is treating zucchini as a botanical vegetable: its fruit is technically a pepo, a berry type, even though cooks use it as a savory vegetable.