The HTTP protocol (Hypertext Transfer Protocol) is an internet protocol that facilitates communication between web clients (such as a web browser) and web servers. It is used to transmit data over the internet and is the foundation of data communication for the World Wide Web. HTTP defines the format and communication rules for web pages, including how the request and response messages should be sent and interpreted. When a user requests a web page, their browser sends an HTTP request to the web server, which then responds with the requested data.