Anchor text is the visible hyperlinked text on the page.The inclusion of important keywords in the anchor text can make a big difference in the final ranking of your site pages. All search engines that matter, give significant weight to the anchor text on your pages. In fact Google even has a special operator: allinanchor:keyword', which picks up text only from within the anchor text of indexed pages.

Ex:<a href=? http://www.domain.com ?> Anchor Text </a>.......