A Uniform Resource Identifier (URI) is a string of characters used to identify a resource on the internet. It provides a way to access and interact with various types of resources, such as web pages, images, or files. A URI can be a Uniform Resource Locator (URL), which specifies the location of a resource, or a Uniform Resource Name (URN), which identifies a resource by name in a specific namespace. URIs are essential for web navigation and communication, as they allow users and applications to locate resources easily. For example, a URI like https://www.example.com directs users to a specific website. By using URIs, developers can create links and references that connect different resources across the internet.