A coronation is the ceremony when a new King (or Queen, let's not be sexist) is officially installed. A coronation is usually quite glitzy and full of pomp.
A coronation is the public handing over of title and powers to a new monarch. Other almost identical terms are enthronement and investiture. The term coronation is also sometimes used in a light-hearted, though sometimes sarcastic way, to describe the ascension of famous non-royal people who have achieved a particular level of public status — such as pop stars, politicians or celebrities. Coronation is derived from the Latin word corona, meaning "crown."