# Embeddings Source: https://customlabs.io/glossary/embeddings/ Updated: 2026-09-13 Foundations # Embeddings Also known as vector embeddings Embeddings are numeric vectors that place similar content close together in vector space. They are the substrate under vector search and RAG, converting a query and a corpus into comparable vectors. Embedding model choice and dimensionality directly bound how good retrieval can be. A mismatched or stale embedding model is a common, silent cause of RAG failure. [Insight: Your RAG demo lied to you](https://customlabs.io/insights/your-rag-demo-lied/)[Capabilities](https://customlabs.io/capabilities/) [← Back to the full glossary](https://customlabs.io/glossary/) ## Related terms [Retrieval-Augmented Generation (RAG) Retrieval-Augmented Generation (RAG) retrieves relevant passages at query time and feeds them into an LLM's context.](https://customlabs.io/glossary/retrieval-augmented-generation/)[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/) ## 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/)