A ceremony is an activity performed at a special time usually with according seriousness. Ceremonies may be done to celebrate an event or rite of passage.
Sometimes, a ceremony may only be done by certain people. A wedding is done by a priest or a Civil Celebrant. The President of the United States is sworn in by the Chief Justice of the United States at his or her inauguration. The British monarch is usually made king or queen by the Archbishop of Canterbury at his or her coronation.
Other ceremonies may mark yearly events like: