Link, Hyperlink
A connection which takes you to another place on a given Web page, to a different Web page, or to another Web site.
In the HTML code, the link is assigned the URL of the Web page it needs to jump to and in some cases to a bookmark which points to a specific place on a Web page.
Internal links are inside a given Web site and external links go to other sites. External links can be outgoing or incoming. Incoming links (back links) are especially important for increasing the searchability of your Web site.
Reciprocal link programs can help increase your links. Link farms (automated link exchanges), however, are not recommended and generally do not help search rank.