Nesting level – SEO WIKI
The nesting level (HC) is the position of a particular page in the overall structure of the site.
The HC is determined by the number of clicks (transitions) that the user makes before he gets from the main page to a specific page.
The main page of the site (face) always has the first level of nesting. Pages that are linked from the main page already have a second level of nesting. The following pages are of the third level and so on. From the point of view of optimization, pages beyond the third level are not optimized, as search robots pay little attention to such pages.