SEO glossary · Updated
LSI keywords: the SEO myth, and what to do instead
"LSI keywords" is an SEO term for related words to add to a page. It borrows the name of latent semantic indexing, a 1980s technique Google doesn't document using.
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LSI keywords are often described as related words you should sprinkle into a page so Google understands its topic. The name comes from latent semantic indexing (LSI), an information-retrieval technique from the late 1980s for finding relationships between words in a small set of documents.
Google's documentation doesn't mention LSI keywords anywhere, and nothing in Google's description of its ranking systems suggests it uses LSI. The idea persists because many SEO tools sell lists of "LSI keywords".
What Google actually describes
| Google system | What it does |
|---|---|
| BERT | Understands how combinations of words express meaning and intent |
| Neural matching | Connects related concepts in queries and pages |
| RankBrain | Relates words to concepts, so a page can rank without the exact words |
| Passage ranking | Judges individual sections of a page for relevance |
These systems understand language far better than LSI could. You don't need to feed them a list of synonyms.
What to do instead
- Cover the topic fully. If people searching "root canal cost" also want to know about crowns, pain and insurance, answer those.
- Use the words your customers use, naturally.
- Answer the related questions people ask, in their own sections with clear headings.
- Don't stuff lists of related terms into a page. That's keyword stuffing, which Google's spam policies cover.
FAQ
Does Google use LSI keywords?+
Google has never documented using latent semantic indexing, and its published ranking systems use modern language models such as BERT and neural matching instead.
Are related keywords still useful?+
Yes, as a way to find questions and subtopics people care about. Write to cover those, not to hit a list of terms.
Sources
- A guide to Google Search ranking systems — Google Search Central
- Spam policies for Google web search — Google Search Central (2026-08-28)
- SEO Starter Guide — Google Search Central (2025-12-10)
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