A URL (Uniform Resource Locator) is a unique address used to identify a specific web page or resource on the Internet. URLs consist of a protocol (e.g. "http" or "https"), a domain name (e.g. "example.com") and sometimes a specific file or resource path (e.g. "/index.html").

When you enter a URL into a web browser, the browser sends a request to the server associated with the domain name asking for the specific resource identified by the URL. The server then sends the requested resource back to the browser, which displays it to the user.

URLs are an important part of the Internet because they provide a way to find and access certain resources online. They are used in a variety of contexts, such as in the address bar of a web browser, in links on web pages and in other contexts where it is necessary to indicate a location on the Internet.