Cadbury is a famous British company that makes chocolate — bars, boxed chocolates, drinks, and seasonal sweets. In Britain the packets are often purple, and the company uses purple a lot in advertising, so people there can spot a Cadbury thing from far away. It began in Birmingham in the 1800s as a family business (the Cadbury family). Their best-known bar is Dairy Milk; they also make things like Creme Eggs. You will see the name in shops in many countries, though actually the taste is not always exactly the same as the British one. It is a company name, not a kind of chocolate in the dictionary sense, so we write it with a capital C. People say it the way they say any well-known brand.