The Webmaster's Lexicon: H

Head	An HTML tag, used to contain other tags that contain information about the document and are not normally displayed. The HEAD element has no attributes and the start and end tag can always be safely omitted as they can be readily inferred by the parser. Information in the HEAD element corresponds to the top part of a memo or mail message. You can always omit both the start and end tags for HEAD.
Hidden	An attribute of the INPUT form tag.
HTML	Hypertext Markup Language. HTML is a markup language used to create hypertext documents that are platform independent. HTML documents are SGML documents with generic semantics that are appropriate for representing information from a wide range of domains. HTML markup can represent hypertext news, mail, documentation, and hypermedia; menus of options; database query results; simple structured documents with in-lined graphic; and hypertext views of existing bodies of information.
HTML_editors	Tools assisting with the creation of web pages.
HTTP	Hypertext Transfer Protocol. An application-level protocol with the lightness and speed necessary for distributed, collaborative, hypermedia information systems. It is a generic, stateless, object-oriented protocol which can be used for many tasks, such as name servers and distributed object management systems, through extension of its request methods (commands). A feature of HTTP is the typing and negotiation of data representation, allowing systems to be built independently of the data being transferred.
HTTP Headers	Information exchanged between the browser and the server. An HTTP transaction consists of a header followed optionally by an empty line and some data. The header will specify such things as the action required of the server, or the type of data being returned, or a status code. The header lines received from the client, if any, are placed by the server into the CGI environment variables with the prefix HTTP_ followed by the header name. Any - characters in the header name are changed to _ characters. The server may exclude any headers which it has already processed, such as Authorization, Content-type, and Content-length.
HTTP Request	HTTP/1.0 allows an open-ended set of methods to be used to indicate the purpose of a request. The three most often used methods are GET, HEAD, and POST.
Hyperlink	A relationship between two anchors, called the head and the tail. The link goes from the tail to the head. The head and tail are also known as destination and source, respectively. A hyperlink is a segment of text (word or phrase), or an inline image (an image displayed as part of the document) that refers to another document (text, sound, image, movie) elsewhere on the World-Wide Web. Hyperlinks in a document are indicated in some way, e.g. in a graphical interface, by color & underlining for text; or by a colored border for an image; an audio clip might be represented by a speaker icon; in a text-based interface, by a number immediately afterwards. When a hyperlink is selected (by mouse click in a GUI, or entering the given number at a prompt in a text interface), the referenced document is fetched from the Internet, and is displayed appropriately (e.g. if its audio, and your workstation is appropriately configured, the sound is played through a speaker).
Hypermedia	A combination of hypertext and multimedia that allows users to move in a non-linear fashion through text, images, sounds, and other information. The runaway success of the WWW and browsers like Mosaic and Netscape is attributable to many interwoven factors, such as the essential simplicity of the "hypertext transfer protocol," the client - server paradigm, and the supporting infrastrucure of the Internet. But the most obvious reason for this success is that these browsers introduced many innovations that hid the arcana of the UNIX-flavored Internet under intuitive and attractive point-and-click graphical user interfaces. The rich resources distributed around the Internet became instantly available to all, computer geek or not, at the click of a mouse button. The basic paradigm exploited is "hypermedia" - multimedia capabilities such as graphic, sound, and movies, linked in a world-wide web of hypertext.
Hypertext	A collection of documents joined by links so that users can read it in a variety of different orders. Hypermedia (or, more loosely, hypertext) documents are documents containing hyperlinks to other documents, anywhere on the WWW. A hyperlink is a segment of text (word or phrase), or an inline image (an image displayed as part of the document) that refers to another document (text, sound, image, movie) elsewhere on the World-Wide Web.