Hypertext Markup Language - HTML is the scaffolding of a web page. It defines the content and structure of a page, and links together all the pieces required to deliver the page's visual layout and interactivity. Elements, tags, attributes, content, flow, phrasing, and more!
The Hypertext Transfer Protocol is at the heart of the web. It is a fairly straightforward communications protocol allowing a wide variety of clients to talk to a wide variety of servers. The ease of use of HTTP has helped lead to the web becoming nearly synonymous with "the internet".