Hacker - Slang term for a technically sophisticated computer user who spends a lot of time at a computer. He or she 'hacks' at the keyboard all the time... A computer enthusiast who enjoys learning everything about a computer system and, through clever programming, pushes the system to it's highest possible level of performance. Also known as crackers, these computer hobbyists are also skilled programmers with a mischievous bent who break into secured computer systems.

Half Duplex - Signal flow in both directions, but only one way at a time. It is sometimes used to refer to activation of LOCAL ECHO which causes a copy of sent data to be displayed on the sending display.

Hardware - The nuts, bolts, and wires of a computer and computer-related equipment, also the actual computer and related machines such as scanners and printers.

Header - The portion of a packet which contains the source and destination addresses, error checking, and other information. A header is also the part of an e-mail message that precedes the body of the message and contains, among other things, the message originator, date and time, and subject lines.

Hertz (Hz) - A unit of measurement of electrical vibrations; one Hz is equal to one cycle per second. Named after the discoverer.

Hit - 1.One visit to a World Wide Web page by a user.Many servers have counters on their home pages to tell how much traffic they are getting. 2.A cache hit is a successful retrieval of data from a cache.

HLP - A Windows HLP Hypertext File - This refers to the computer filename extension of Windows help files (like this one). You may load HLP files using Windows File Manager or File Explorer and simply double-clicking on them

Home Page (or Homepage) - Several meanings. Originally, a Home Page was defined as the Web page your browser was set to use when it was started up. The more common meaning now refers to the main Web page for an organization, business, person or simply the main page out of a collection of Web pages.

Host (Host System) - Another name for a data server or web page server located on the Internet or a Bulletin Board System (BBS)

Hotspot - A hotspot is an area of a screen that works like a button but doesn't look like a button. If you click it some task or program will begin just like clicking a button with your mouse pointer!

Hz (Hertz) - The number of cycles per second of an electromagnetic wave; one Hz is equal to one cycle per second.The name comes from Heinrich R.Hertz, the German physicist who discovered electromagnetic waves.

HTML (HyperText Markup Language) - The coding language used to create Hypertext Documents for use on the World Wide Web. HTML actually looks a lot like old-fashioned typesetting code, where you surround a block of text with codes that indicate how it should appear in a document. Additionally, in HTML you can specify that a block of text, or a word, is linked to another file on the Internet.

http (Hyper Text Transfer Protocol) - Refers to the protocol used to load or transfer a web page from an internet website server. These 'addresses' starting with HTTP are usually typed into the top of a web browser like Netscape or MSIE to loadup a specific web page.

Hub - A hardware device that performs data error checking on an Ethernet network. Cable connects each PC’s network adapter to the hub. Internet sharing ~ The ability of multiple PCs to access the Internet over a single modem connection using a single Internet account.

Hyperlink - A connection between two anchors (web page links). Clicking on one anchor will take you to the linked anchor. Can be within the same document/page or two totally different documents.

Hypertext - Text that contains links to other documents - words or phrases in the document that can be chosen by an Internet user which causes another document to be retrieved and then displayed.