What is semantic search?
Quick Answer
Semantic search uses AI to understand the meaning behind search queries and documents rather than just matching keywords. It finds results based on conceptual similarity, so searching for 'annual leave policy' also returns documents about 'holiday entitlement' and 'time off procedures'. Semantic search dramatically improves search accuracy and is the retrieval mechanism behind RAG systems and modern enterprise search.
Summary
Key takeaways
- Understands query meaning rather than just matching keywords
- Finds relevant results even when exact terms are not used
- Powered by embedding models that represent meaning as vectors
- Significantly outperforms keyword search for natural language queries
How Semantic Search Works
Business Applications of Semantic Search
FAQ
Frequently asked questions
For natural language queries, semantic search significantly outperforms keyword search. For exact-match searches (product codes, names), keyword search remains valuable. The best systems use hybrid search combining both approaches.
Choose an embedding model, generate embeddings for your content, store them in a vector database, and build a search interface that converts queries to embeddings and finds similar content. Many platforms offer managed semantic search services.
Embedding generation costs are minimal, typically pence per thousand documents. Vector database hosting costs £50 to £500+ per month depending on scale. The main investment is in integration and tuning for your specific use case.
Modern embedding models handle common technical terminology well. For highly specialised jargon, domain-specific embedding models or fine-tuned models perform better. Hybrid search combining semantic and keyword matching ensures technical terms are matched even when the embedding model is unfamiliar with them.
Semantic search can significantly improve search quality but is best deployed alongside existing keyword search in a hybrid approach. This captures both exact-match precision for specific terms and semantic understanding for natural language queries.
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