Definition - What does Link Rot mean?
Link rot is a slang term for hypertext links that are broken. Link rot is created when a Web page is moved, taken down or reorganized. Clicking on a rotten link usually results in a 404 error, which includes a message that the page cannot be found.
Link rot, also spelled linkrot, is also referred to as link death or links to nowhere.
Techopedia explains Link Rot
Dead links are created all the time as websites go down, but link rot refers to pages that are unlikely to return to the linked address. Link rot that occurs due to website reorganization can be corrected with redirects. However, some link rot is inevitable as websites do simply disappear. Moreover, when there are deep links within a website, they may not warrant the time and effort to create a redirect for a page that is rarely visited.