A courgette is the French term for what we Americans call a zucchini. It is a dark green vegetable speckled with white spots on its skin. It is a cylindrical summer squash. While it looks like a dry version of a cucumber, the two are not related.
The term courgette is most often used in the UK, Ireland, France, New Zealand, South Africa, and Kenya. The term zucchini is used in the US, Australia, and Italy. The term used varies greatly on the peoples who live in your area, and any American or European influence that may have been present in its history.
In produce markets, “courgette” may be used interchangeably with zucchini. If the market has a vast and varied selection of vegetables, the courgette may refer to an immature or “baby” zucchini sold alongside the full grown zucchini.
Many squashes originate in the Americas, however, the zucchini is an exception. It was developed in northern Italy and then brought over by immigrants in the late 1900s.