Canonical URL
The link tag that tells search engines which URL is the real one, so duplicate or parameterized pages don't split ranking.
A canonical URL, set with a link rel="canonical" tag, names the definitive address for a page. When the same content is reachable at several URLs — trailing slashes, tracking parameters, http vs https — the canonical tells search engines which one to index and credit, consolidating ranking signals onto a single URL.
<link rel="canonical" href="https://yoursite.com/page" />