Semantic SEO is the practice of optimising content for meaning and topics rather than individual keyword strings. Modern search engines understand concepts, relationships and context, so the goal is to cover a subject the way an expert would. It shapes both keyword research and how you write.
How search became semantic
Early search engines matched words. Since the Knowledge Graph (2012), Hummingbird (2013), RankBrain (2015), BERT (2019) and MUM (2021), Google has been able to understand synonyms, intent, context and entities. It knows that “Big Smoke” can mean London and that a query about “jaguar speed” is probably about the animal unless cars are mentioned.
What are entities?
An entity is a distinct, identifiable thing: a person, place, organisation, product or concept. Google stores facts about entities and the relationships between them in its Knowledge Graph. Pages that mention the right related entities help Google place them in context.
For example, a page about “making sourdough” naturally mentions starter, levain, hydration, autolyse, banneton, Dutch oven and gluten. Missing most of those suggests a shallow page.
The truth about LSI keywords
You will see advice to add “LSI keywords”. Latent Semantic Indexing is an old information-retrieval technique that Google does not use. What people usually mean is related terms and entities, which do help. Ignore lists of random synonyms and focus on what a complete answer contains.
How to do semantic SEO
- Study the results: list the sub-topics and terms every top page covers.
- Answer related questions: use People Also Ask and forums.
- Include key entities naturally, with definitions where useful.
- Structure clearly with headings for each sub-topic. See header tags.
- Use schema markup to state entities explicitly, such as your organisation, authors and products. See schema markup.
- Link related pages so the topic relationships extend across your site.
- Build clusters to develop topical authority.
Semantic SEO and AI search
Large language models are semantic by design. Content that clearly explains concepts and relationships is easier for them to understand, summarise and cite, which is why semantic SEO supports generative engine optimisation.
Tools that help
Content optimisation tools such as Surfer, Clearscope, Frase and MarketMuse compare your draft with top results and suggest missing terms. Use them as a checklist, not a target score.
Frequently asked questions
Do I still need exact-match keywords?
Use the main phrase in the title, H1 and intro. Beyond that, write naturally.
Is semantic SEO only for long articles?
No. Product and category pages benefit from covering features, uses and specifications too.
Related terms
See long-tail keywords, SEO content writing and the SEO encyclopedia.
Mr. SEO
Mr. SEO is the webmaster at SEO TT - SEO tips and tricks, a publication about all things SEO related.