404 Error
01 Definition
404 Error meaning: An HTTP status meaning the requested page could not be found on the server.
A 404 error is the HTTP status code a server returns when a requested URL does not exist. It tells browsers and crawlers the page is not found, though it may return later. Search engines eventually drop 404 URLs from the index, but the response does not promise the page is gone forever.
Also called
Why it matters
How 404 Error fits the work
404s are normal on any site, but broken internal links and lost backlinks pointing to 404s can waste crawling and hurt user experience, so monitoring them matters.
In context
After removing a discontinued product, the URL returned a 404 error, and the team redirected only the pages that had valuable backlinks or traffic.
Practical note
A few 404s are healthy and expected; you do not need to redirect every one. Redirect a 404 only when a relevant replacement page exists, otherwise a plain 404 is fine.