Semantic Search

Categories:SEO & AEO

Semantic search is retrieval based on meaning rather than exact wording, matching a query to content by comparing concepts instead of strings. It is why one well-written page can rank for hundreds of phrasings it never contains, and why writing for a topic beats writing for a keyword list.

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How it works, roughly

Text is converted into vectors, numeric representations that place similar meanings near each other. A query becomes a vector too, and retrieval finds the content sitting closest to it, whether or not the words match.

This is the same machinery behind generative answers. A model retrieves candidate passages semantically before it writes anything, which is why passage quality matters more than keyword placement.

Keyword matching against semantic matching
Keyword matchingSemantic matching
Matches onStrings in the textMeaning of the passage
RewardsExact phrase placementTopic coverage and clarity
PenalisesLittleRepetition and thin content
ImplicationWrite for a phraseWrite for a question

What it changed for writing

Exact-match keyword density stopped being useful and started being a liability. Repeating a phrase to hit a target now reads as thin to systems that were built to recognise meaning, and Princeton's 2024 research on generative engines found keyword stuffing performed worse than doing nothing.

  • Cover the topic properly rather than chasing one phrase
  • Use the vocabulary your readers use, including synonyms and adjacent terms
  • Write self-contained sections, since retrieval works at passage level
  • Define your terms, because clear definitions are easy to match and easy to quote

Why it matters for B2B marketing teams

This is permission for B2B teams to stop writing thin pages for keyword variants. One thorough page about a problem will outperform six shallow pages about six phrasings of it, and it gives generative systems something substantial enough to quote.

Frequently asked questions

Do keywords still matter?+

As evidence of topic and intent, yes. As strings to hit a density target, no. Keyword research still tells you what people want and how they phrase it, which is useful for deciding what to write and how to title it.

What is the difference between semantic search and vector search?+

Vector search is the technique, comparing numeric embeddings to find similar meaning. Semantic search is the outcome those techniques produce. In practice the terms are used interchangeably, with vector search implying the implementation detail.

Related terms

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