A tea urn is mainly used for serving a large number of people. It is a large container that can hold a significant amount of hot water, which is used to make tea. Tea urns are commonly used in events like conferences, meetings, and parties, where a lot of people need to be served with tea quickly and efficiently. The size of a tea urn can vary, depending on the number of people it is intended to serve, but they are generally designed to serve a group of people rather than just a few individuals.