# Retrieval-Augmented Generation (RAG)

Source: https://customlabs.io/glossary/retrieval-augmented-generation/
Updated: 2026-09-13

Foundations

# Retrieval-Augmented Generation (RAG)

Also known as RAG

Retrieval-Augmented Generation (RAG) retrieves relevant passages at query time and feeds them into an LLM's context.

It answers from your own data instead of the model's training memory, trading a knowledge problem for a retrieval-quality one.

Chunking, embeddings and ranking decide whether the answer is grounded or just a plausible-sounding guess.

Most complaints that the AI does not know your data point to a RAG pipeline defect, not a model limit.

[Insight: Your RAG demo lied to you](https://customlabs.io/insights/your-rag-demo-lied/)[AI Integrations](https://customlabs.io/services/ai-integrations/)

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## Related terms

[Embeddings Embeddings are numeric vectors that place similar content close together in vector space.](https://customlabs.io/glossary/embeddings/)[Vector Search (Semantic Search) Vector search finds the nearest matches to a query by comparing embeddings, not exact keywords.](https://customlabs.io/glossary/vector-search/)[Chunking Chunking splits source documents into smaller passages before embedding, so retrieval returns focused text.](https://customlabs.io/glossary/chunking/)[Hallucination A hallucination is a confident, fluent output that is factually wrong or unsupported.](https://customlabs.io/glossary/hallucination/)

## More in Foundations

[Context Window The context window is the maximum text, measured in tokens, a model can consider at once.](https://customlabs.io/glossary/context-window/)[Token A token is the basic unit of text an LLM reads and writes.](https://customlabs.io/glossary/token/)[Model-Agnostic Architecture A model-agnostic architecture lets an application swap or route between LLM providers without a rewrite.](https://customlabs.io/glossary/model-agnostic-architecture/)[Fine-Tuning (vs RAG) Fine-tuning trains a model's weights on your own examples, changing its behavior directly.](https://customlabs.io/glossary/fine-tuning/)