an endorsement or recommendation that your site is good, and search engines want good sites to be at the top of their search results
an external link that appears on a different site and points toward your site, while an outgoing link is an external link that appears on your site but points toward a different site
a simply a piece of hyperlinked text that takes a visitor to a page on your web site when clicked
a link from a site outside of your site.
A link on another web site that is to your web site.