> ## 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.

# Semantic Center of Gravity

> The semantic center of gravity is the dominant conceptual direction of a passage's embedding vector.

*Core concept* · *AI Search Infrastructure*

## Definition

The semantic center of gravity is the dominant conceptual direction of a passage's embedding vector. A passage with a single, clear semantic center produces an embedding that points consistently toward one cluster in vector space. A passage with multiple competing topics has a diffuse embedding pulled in multiple directions simultaneously.

## Why It Matters for AI Search

The semantic center of gravity is the mechanism behind the structural rule of one question per section. A passage can be long and technically detailed, as long as everything in it contributes to the same conceptual direction. The moment a section begins addressing a second question, the embedding starts drifting — the vector moves away from the first cluster without fully entering the second. Both retrieval targets suffer.

## Related Terms

<CardGroup cols={2}>
  <Card title="Semantic density" href="/ai-search-glossary/semantic-density" />

  <Card title="Embedding drift" href="/ai-search-glossary/embedding-drift" />

  <Card title="Topic coherence" href="/ai-search-glossary/topic-coherence" />

  <Card title="Embedding" href="/ai-search-glossary/embedding" />

  <Card title="Cosine similarity" href="/ai-search-glossary/cosine-similarity" />
</CardGroup>

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