A single request from a Web browser for a single item from a Web server; thus, in order for a Web browser to display a page that contains three graphics, four hits occur at the server: one for the HTML page, and one for each of the three graphics. Hits are often used as a rough measure of visits on a server.

Source: Sweeney, Susan

Any computer on a network that can hold available to other computers on the network. It is quite common to have one host machine provide several services to other machines, such as WWW and Usenet.

Source: Sweeney, Susan

HTML, short for HyperText Markup Language, is the predominant markup language for the creation of web pages. It provides a means to describe the structure of text-based information in a document — by denoting certain text as headings, paragraphs, lists, and so on — and to supplement that text with interactive forms, embedded images, and other objects. HTML is written in the form of labels (known as tags), created by greater-than signs (>) and less-than signs (<). HTML can also describe, to some degree, the appearance and semantics of a document, and can include embedded scripting language code which can affect the behavior of web browsers and other HTML processors.

HTML is also often used to refer to content of the MIME type text/html or even more broadly as a generic term for HTML whether in its XML-descended form (such as XHTML 1.0 and later) or its form descended directly from SGML (such as HTML 4.01 and earlier).
 

Source: wikipedia.org

Hypertext Transfer Protocol (HTTP) is a method used to transfer or convey information on the World Wide Web. Its original purpose was to provide a way to publish and retrieve HTML pages.

Source: wikipedia.org