Pageantry is the grand public show around a big event: special clothes, flags, music, slow walking in a line, everything made to look rich and important. A royal wedding has pageantry; a national-day parade has pageantry. The word names the colour and formal air of the whole scene, not one person in a costume. A pageant is often the event itself; pageantry is the dressed-up feeling that event is wrapped in. You will hear it in news about kings and state days, and in history writing, more than in ordinary chat. It feels a little grand and bookish. Though actually, people also use it with a tired smile, for empty show — a lot of dressing up and not much underneath. We speak of pageantry, not “a pageantry.”