Google’s system for understanding individual passages within a page to help assess that page’s relevance to a search.
Passage ranking helps Google assess a page’s relevance by understanding individual sections within it. The passage contributes to understanding the page; it is not automatically a separately published or separately indexed document. A long page can contain a useful answer without every section needing its own URL.
This is different from designing page structure. Headings, paragraphs and navigation should make information understandable to readers regardless of how a search system analyzes it. A descriptive section can help someone find the relevant explanation, but adding a heading does not guarantee that the section will receive a special search treatment.
Choose page boundaries based on the task. A short supporting answer may belong inside a broader guide, while a substantial topic with a distinct purpose may justify its own page. Do not split every paragraph into a thin page or combine unrelated subjects into a huge document merely because passage ranking exists.
Takeaway: Organize content into coherent, useful sections. Keep the distinction between a page, a section and a search-result presentation clear when planning or measuring content.
Example
A detailed guide to choosing a commercial refrigerator includes a section about doorway clearance. That section answers a specific installation question while remaining part of the broader buying guide. The business does not create a separate near-empty URL for each measurement mentioned.
What to check
Check that section headings describe the information below them and that readers can navigate long pages. Do not report a passage as a new indexed page or promise a featured snippet because a section was added.
For more detail, see Google ranking systems guide.