an alphabetical list of words relating to a specific subject, text, or dialect.
Anchor text is the clickable words and/or characters in a hyperlink. It is often displayed on a web page by a browser as blue and underlined characters to make it stand out from the rest of the text.
Search engines use anchor text to determine what the hyperlinked page is about. Anchor text should reflect the content of the page the hyperlink is pointing to. When optimising a page for search engines, including important keywords in the anchor text can make a difference in the ranking of your page.
Search engines have different metrics for determining search engine rankings, and link relevancy is one of them. The source page's content and the content of the anchor text helps determine link relevancy.