Heading Tag

An HTML tag of 6 sizes. Search engines can rank a keyword higher if it appears in a larger heading.
 

HiddenText/Tiny Text
Placing same color characters on the same color background causes them to be hidden. This technique was popular for awhile, but search engines quickly caught on and began banning sites for it.
Hit
A request for a file on a webserver. Most often these can been graphic files and documents. In more modern lingo, website owners referer to a HIT referrers as a request for documents only, while system administrators who are cheifly concerned about server performance, refer to it as
any file request..
Hotbot
A search engine owned by Wired Digital, a division of Lycos. Hotbot uses the Inktomi search service to present results. It also uses the Direct Hit service to help rank pages based upon click through counts.
HTML
HyperText Markup Language. The programming language of tag commands used in web pages.
HTML Link
A hyper link within a web page. You clicked on an HTML link to get to this page.
  HTTP
HyperText Transfer Protocol. The agreed upon system to transfer data between a web server on the browsers.