HTTP
HTTP, which stands for HyperText Transfer Protocol, is the network protocol used to transfer data over the Internet.
When a user visits a Web site, his or her browser sends an HTTP request to the Web site’s server, which responds by sending the requested page data.
HTTP is a fundamental part of how the web works, but it is not secure in itself, which is why it has been replaced on many websites by HTTPS, a new standard promoted (among others) by Google for greater privacy of sensitive user data.