What is the name of Wikipedia's policy that forbids original research?

Wikipedia’s policy that forbids original research is called “No original research.”

The policy requires Wikipedia articles to summarize knowledge that has already been published in reliable sources. Editors are not supposed to introduce their own theories, unpublished findings, personal analysis, or conclusions that cannot be directly supported by sources. This helps keep Wikipedia an encyclopedia rather than a venue for new research or advocacy.

A related restriction is the ban on “synthesis”: even when individual facts are published, editors cannot combine them to imply a new conclusion unless a reliable source has made that connection. This is a common point of confusion because an editor may believe a conclusion is obvious, yet Wikipedia still requires published support.

“No original research” works alongside Verifiability and Neutral point of view. Verifiability asks whether readers can check a claim in reliable sources; neutral point of view concerns fair representation of significant viewpoints. Consensus is the process editors use to resolve disagreements, not the policy that bans original research.