an alphabetical list of words relating to a specific subject, text, or dialect.
This is a form of link building where a clickable text (usually the keywords) is created within the main content of a web page. These links are built either from pre-existing content of a website or newly posted content.
Contextual links help in navigation of the website and point the user towards relevant content which exists deeper within a website. Contextual links can point to the same domain or a different one.