BM25

The lexical half of hybrid search: a ranking function that scores a document by how often a query term appears in it, discounted by how common the term is across the corpus and by document length. It finds exact strings that embedding similarity blurs, a part number, a company name that is also an ordinary word. It cannot find a paraphrase, which is why retrieval systems pair it with dense retrieval rather than choosing one.

Terms this definition uses

Hybrid search · Corpus · embedding · retrieval · dense retrieval

Answer engines and retrieval

How a generated answer gets made, and what your page is competing for inside it.

AEO · GEO · AI visibility score · share of voice · prompt set · brand mention · RAG · grounding · training data · embedding · chunking · context window · token · hallucination · refusal · AI Overview · answer engine · citation · retrieval · hallucinated attribution · Hybrid search · Re-ranking · Passage ranking · Query fan-out · Chunk boundary · cross-encoder · AI Mode · information gain · dense retrieval

← Chunk boundary · cross-encoder →

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