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SEO Glossary/LSI Keywords

What is LSI Keywords?

LSI keywords (Latent Semantic Indexing keywords) are terms and phrases semantically related to your primary keyword. In modern SEO, the concept refers broadly to related terms that help search engines understand content context and topical coverage.

LSI keywords (Latent Semantic Indexing keywords) is a term commonly used in SEO to describe words and phrases that are semantically related to a primary keyword. For example, LSI keywords for "coffee" might include "beans," "espresso," "caffeine," "brewing," "roast," and "barista."

A note on terminology: while the SEO industry widely uses "LSI keywords," the technical LSI algorithm from the 1980s isn't what Google actually uses. Google employs far more advanced NLP and machine learning systems (BERT, MUM, etc.) for understanding semantic relationships. However, the practical concept — using related terms to signal topical depth — remains valid and important.

The practical application of related/LSI keywords in SEO includes:

  • Contextual signals: Related terms help search engines understand what your content is about and disambiguate meaning (e.g., "apple" with "orchard" vs. "iPhone")
  • Topical depth: Including related concepts shows comprehensive coverage of a subject
  • Natural language: Good content naturally includes related terms because thorough coverage requires discussing adjacent concepts
  • Ranking breadth: Content with strong semantic coverage ranks for more keyword variations

You can find related terms through Google's related searches, Google autocomplete, competitor content analysis, NLP tools, and content optimization platforms that identify the semantic themes top-ranking pages cover.

Why it matters for SEO

Including semantically related terms in your content signals topical comprehensiveness to search engines. Content that naturally covers related concepts is perceived as more thorough and authoritative than content that repetitively uses a single keyword. This semantic coverage helps you rank for a broader set of queries and demonstrates the kind of depth that modern search algorithms reward.

How Ascend helps

Ascend's content briefs identify the semantically related terms and topics that top-ranking content covers. Rather than just providing a keyword list, the AI analyzes the full semantic landscape of your target topic, ensuring your content includes the contextual terms and concepts that signal comprehensive coverage to search engines.

Put this into practice

Generate an SEO brief that accounts for lsi keywords — in under 60 seconds.

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Related Terms

Semantic SEONLP SEOKeyword DensityContent BriefKeyword Clustering

FAQ

Does Google actually use LSI?
Google has confirmed it doesn't use the specific LSI algorithm (which was designed for small document sets). However, Google does use advanced NLP to understand semantic relationships between words. The SEO concept of using related terms remains valid.
How do you find LSI/related keywords?
Check Google's related searches and autocomplete, use tools like Ascend that analyze semantic coverage, study competitor content for commonly used terms, and use NLP analysis tools like Google's Natural Language API.
How many related terms should you include?
There's no specific number. Include related terms naturally as you write comprehensive content about your topic. If you're writing thoroughly, related terms will appear organically. Don't force them in — focus on covering the topic well.