> ## Documentation Index
> Fetch the complete documentation index at: https://wiki.platelunchcollective.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Passage-level Retrieval

> Passage-level retrieval is the retrieval of individual sections or passages from a document rather than the document as a whole.

*Core concept* · *AI Search Infrastructure*

## Definition

Passage-level retrieval is the retrieval of individual sections or passages from a document rather than the document as a whole. Modern RAG systems embed and retrieve at the chunk level — the retrievable unit is the passage that answers a sub-query, not the page that contains it.

## Why It Matters for AI Search

Passage-level retrieval is the mechanical reason that page-level optimization is insufficient for AI citation. A page optimized for the parent query may contain no passage that cleanly answers any individual sub-query. A page structured around sub-query-answering sections — one question per section, answer-first — produces multiple distinct retrievable units from a single page. The page builds topical authority; the sections earn citations.

## Related Terms

<CardGroup cols={2}>
  <Card title="Sub-query" href="/ai-search-glossary/sub-query" />

  <Card title="Chunking" href="/ai-search-glossary/chunking" />

  <Card title="Semantic density" href="/ai-search-glossary/semantic-density" />

  <Card title="Retrieval readiness" href="/ai-search-glossary/retrieval-readiness" />

  <Card title="Content hub" href="/ai-search-glossary/content-hub" />
</CardGroup>

## Relevant Plate Lunch Collective Services

[Citation-Ready Content](https://www.platelunchcollective.com/services/citation-ready-content)  [AI SEO](https://www.platelunchcollective.com/services/ai-seo)  [Answer Engine Optimization](https://www.platelunchcollective.com/services/answer-engine-optimization)