A placard is a sign or notice that can be installed in a public place, like a small card, sign, or plaque. It can be attached to or hung from a vehicle or building to indicate information about the vehicle operator or contents of a vehicle or building. Placards can be used for various purposes, such as advertising, announcing a campaign rally, displaying information to the user in computer graphical user interfaces, or carrying a message in a protest. In Model United Nations, the paper nameplate of a delegation is referred to as a "placard". The term "placard" can also refer to a large notice that is carried in a march or displayed in a public place. The word "placard" comes from the Old French word "plaquier," which means "to plaster or to lay flat".