Semantic Search
Semantic search is the engine's ability to understand what a query means rather than just matching its words. Google moved to meaning-based matching years ago; LLMs made it universal. Search for 'what to do for a sore back' and the engine understands you're asking about back pain - and so do the AI engines. For SEO, semantic search means the page doesn't need the exact keyword; it needs to genuinely answer the question behind it.
Why It Matters
Semantic search is why the old tactics died. Keyword density, exact-match domains, stuffing - all optimisations for a machine that couldn't understand words. Modern engines understand intent, context, entities and relationships. That's why content written for humans ranks, and content written for keywords gets ignored.
The AI layer extends it. LLM-based search doesn't just understand meaning; it synthesises it. The page that covers the topic deeply - entities, relationships, the actual answer - is the page the system can work with. Shallow keyword-matched pages have nothing for the model to synthesise.
In Practice
Write about topics, not keywords. Answer the question fully, cover the related subtopics, name the entities involved. Use natural language - the way your customers speak - because the engines now match meaning to it. Structure content so the relationships are explicit: headers that ask the real questions, linked entities, schema that says what things are.
Stop checking keyword density. Check whether the page answers the query better than everything else ranking for it. If it does, the semantic engines will find you.
Common Mistakes
Still optimising for exact-match keywords as if it's 2005, or producing shallow pages that match the query but answer nothing. The engines understand meaning now - a page of keyword-matched fluff reads as exactly what it is.
Sources & Further Reading
Where to verify this yourself - Google's own documentation, industry reporting, and how we apply it at Underdog. Don't take our word for it; check the source.
Related Terms
Glossary
Search Intent
The reason behind a search query - matching it is more important than matching keywords.
Glossary
Keyword Research
Finding what your audience searches for - the foundation of every SEO strategy.
Glossary
Generative Engine Optimisation (GEO)
The practice of getting your brand cited by AI answers instead of just ranked on Google. Optimising for being the source, not just the link.
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