An internal link is a hyperlink that points from one page on a website to another page within the same domain. These links are the foundation of the information architecture and navigational structure of any website.
Conceptually, internal links serve three main functions: 1) Navigation: They help users navigate the site; 2) Authority Distribution: They distribute link juice within the domain, directing authority to the most important pages; and 3) Semantic Context: They help search engine crawlers understand the relationship and relevance between different pages.
Strategic internal linking is a key element of on-site optimization (On-Site SEO). By using relevant anchor text in internal linking, SEOs can increase the thematic relevance of target pages for specific keywords.