The chili pepper, chilli pepper, is the fruit of the plants from the genus Capsicum. Even though chilis may be thought of as a vegetable, their culinary usage is generally as a spice, the part of the plant that is usually harvested is the fruit, and botany considers the plant a berry shrub.
The name, which is spelled differently in many regions comes from Nahuatl via the Spanish word chile. The term chili in most of the world refers exclusively to the smaller, hot types of capsicum. The mild larger types are called bell pepper in the USA, simply pepper in Britain, Canada and Ireland, capsicum in India and Australasia, and paprika in many European countries.(Wikipedia.org)