Noindex
A directive, set via a meta robots tag or an HTTP header, that tells search engines to keep a specific page out of their index so it never appears in results. The page can still be crawled and its links followed, but it will not surface for any query.
Why It Matters
Noindex gives precise control over which pages compete in search, keeping thin, duplicate, or private pages like thank-you screens and internal search results out of the index while preserving them for users.
Common Mistake
Blocking a noindexed page in robots.txt as well, which stops crawlers from ever seeing the noindex directive, so the page can linger in the index. Leaving noindex on after a staging launch also deindexes live pages.