Passage Ranking (Passage Indexing)
Passage ranking is Google's ability to identify and rank individual, clearly delimited sections within a longer page as relevant to a search query, even when the overarching topic of the page is broader. As a result, a single paragraph of a long article can appear in the search results even if the rest of the page covers a different focus.
In practice
The formerly common term “passage indexing” is misleading – Google still indexes whole pages and merely assesses individual sections separately. This means that individual sections of long content can rank or be cited independently of one another, instead of only the page as a whole being assessed. It underlines the value of clear subheadings and self-contained, well-structured paragraphs that make sense without the context of the whole article. This "answer first" writing style, where the key statement of a section comes right at the start, is also a central practice in AEO (Answer Engine Optimization).