HTML hypertext markup language.
hypertext: (linear) text that has links to other [hyper]texts, forming a web of interconnected documents.
markup language: notation that indicates the structure of a document.

HTTP hypertext transport protocol.
protocol: the rules and message formats used by networked computers to communicate.
HTTP is the part of the Internet protocols (TCP/IP) used by web browser (client) and web server to get web pages.
Browser sends a Request (GET or POST) to a server for a "resource", server sends a Reply with the resource.
URL: universal resource locator. Internet address.
http://serverName/folder/Path/filename

Web page Layers

0. content (text & images & multimedia)
1. structure: HTML. What it is.
   • block-level elements: paragraphs, headings, lists, tables etc
   • inline elements: img, em, a (links) etc.
   • structural elements: sections, nav, aside, header, footer etc.
2. presentation: CSS. How it looks, how the elements are laid out.
   • text formatting: colors, fonts, sizes
   • margins, borders, padding, color, background images of blocks
   • positioning & page layout
3. behavior. How it interacts, if any.
   • Javascript: part of the page
   • client-side: Java applet, Flash
   • server-side programs: ASP, Java, PHP etc. Typically interact with a database.