Interpol is the short name of a big international police organisation. Its job is to help police in different countries share facts, find people, and follow crime that crosses a border. You will see the name in news about wanted people, stolen passports, or crime that is not stuck in one country. It is a proper name, so we write Interpol with a capital letter. Though actually, Interpol does not usually knock on doors and make the arrest itself. It is more like a shared desk: it passes the facts, and each country’s own police do the arresting under that country’s law. Film stories often make Interpol look like a world police force with its own guns; real life is quieter and more about paper, databases, and asking another country for help.