Complete guide to LSI keywords and semantic SEO

Search engines have evolved into language models capable of understanding context and intent, so the combination of semantic keywords, quality content and attention to the user experience is the surest route to position in 2025 and in the future.

Definition of latent semantic indexing keywords

So-called LSI keywords are terms conceptually related to a main keyword and help search engines better understand the context of a document.

These are not exact synonyms but rather words associated with the same semantic field; for example, for digital marketing terms such as LSI are considered SEO, online advertising or social networks.

The Latent Semantic Indexing (LSI) technique emerged in the 1980s to identify patterns of word co-occurrence, but it was not designed for a corpus the size of the modern web. Google confirmed that it does not use LSI as a ranking factor; its algorithms use deep learning models to understand language and search intent. Even so, writing with semantically related terms makes it easier for modern systems to correctly interpret content.

What are LSI keywords for in SEO

Using semantically related keywords in your texts provides several advantages.

First, it improves the relevance of the content because it provides a broader picture of the topic and helps engines understand what the page is about. It also reduces the risk of overoptimization: diversifying vocabulary avoids Keyword stuffing or saturation of the same key phrase, a practice penalized by Google.

Another advantage is that it makes it easier for search engines to understand, since they analyze the entire content and not just the exact words. Finally, the use of related terms improves the user experience, because the text is more natural and pleasant to read. Integrating these words organically can increase rankings in related queries, attract qualified traffic and increase page time.

How to find LSI keywords for my content

Finding semantically-related terms is simple if you know where to look. Some useful strategies include:

• Search for related terms on Google: When you type in a keyword, Google search suggestions and related searches at the bottom of the page show associated queries that can serve as inspiration. These suggestions are based on what other users are looking for and help to discover relevant contexts.
  
• Take advantage of Google Autocomplete: Automatic suggestions offer variations and common questions when you type a phrase in the search bar.
  
• Use SEO tools: platforms such as Ahrefs, Semrush and LSIGraph analyze large volumes of data to suggest semantically related terms. There are also free tools such as Google Keyword Planner, Answer The Public, Keyword Everywhere and Keywords Tool.
  
• Analyze the competition: reviewing the best-positioned articles makes it possible to identify what secondary terms they use and how they structure their content.
  
  

These combined tactics allow you to create a list of LSI keywords adapted to the topic and the search intent of your audience.

Examples of LSI keywords

To understand how LSI keywords work, you should look at specific examples. The following table shows several topics with their main keywords and some semantically related terms:

Theme

Main keyword

LSI words/related terms

Fountain

Digital marketing

digital marketing

SEO, online advertising, social networks

Seology Agency

Digital Marketing (English)

Digital marketing

social media marketing, search engine optimization, pay‑per‑click advertising

LowFruits

Ironing tool

iron for ironing

steam, horizontal board, clothes

Moonlight Marketing

These terms are not exact synonyms; instead of repeating the main keyword, associated concepts are used that provide context and enrich the text.

Importance of semantic keywords

The use of semantic keywords or LSI not only benefits positioning, but also improves the quality of the content. Here are the main reasons:

• They provide relevance: search engines can better interpret the general topic and provide more accurate results.
  
• They prevent keyword spam: diversifying terms reduces the possibility of falling into keyword stuffing and possible penalties.
  
• They facilitate modern semantic indexing: Although Google doesn't use LSI, it uses language models such as BERT that analyze the context of sentences. Content rich in semantic terms helps these models to understand it better.
  
• They improve the user experience: a natural text with a variety of terms maintains the reader's interest and favors metrics such as length of stay.
  
• They reinforce thematic authority: covering a broad semantic field shows depth of knowledge and can improve signs of experience, authority and reliability (E‑E‑A‑T).
  
  

Better tools for finding LSI keywords

‍

widget

Type/cost

Description

LSIGraph

Freemium

Generate lists of semantic terms based on a main keyword. It offers free basic analysis and paid options for deeper studies.

Google Keyword Planner

Gratuita

Google tool that helps find keyword ideas and estimate search volumes. It includes suggestions for related terms.

Answer The Public

Freemium

It collects questions and phrases that users type in search engines, showing common semantic variations.

Ahrefs/Semrush

For a fee

Complete SEO suites that analyze keywords, suggest related terms and allow you to study the competition.

Keyword Everywhere

Freemium

Browser extension that displays search volumes and related queries in real time.

Keywords Tool

For a fee

It generates semantic keywords and long-tail variations; very useful for in-depth research.

Google Suggest/Related Searches

Gratuita

Automatic suggestions and related searches on Google reveal terms that users frequently search for.

The following table summarizes some popular tools for researching related terms. It includes free and paid options so that anyone, from beginners to professionals, can explore their semantic field:The combined use of these tools provides a broad view of the vocabulary related to your topic and helps you create more complete content.

Difference between LSI keywords and long-tail keywords

LSI keywords and long-tail keywords are not the same thing. A fundamental difference is length: long-tail words usually have three or more words and are very specific queries, such as “large iron” or “how to use a clothes iron”. These phrases have less competence and tend to reflect a more specific search intention, so they can convert better.

Instead, an LSI word need not be long or include the exact key phrase; it can be a single term that is conceptually related to the topic. For example, for a page about iron for ironing, terms such as vapour, horizontal table or clothing they are LSI words. The following table summarizes the main differences:

Understanding these differences allows us to combine both strategies: using semantically related words to improve overall relevance and long-tail words to capture specific niches.

How to use LSI keywords to improve my blog ranking

Incorporating semantic words into a blog requires balance and planning. Follow these steps to do it effectively:

1. Research and planning: Before writing, do extensive research on keywords and related terms. Plan your content around a central theme and organize the LSI words you want to incorporate.
   
2. Natural wording: use the words LSI in an organic way. Avoid overloading the text; the goal is to make the reading fluid and natural. Keyword abuse can impair user experience and ranking.
   
3. Clear structure: include related terms in titles and captions to improve the organization of the article. The headers should reflect the variations of the queries you want to address.
   
4. On‑page optimization: add semantic words to meta descriptions, tags Alt of the images and in the internal links. This helps to diversify the language without losing coherence and improves accessibility.
   
5. Review and update: review your content periodically to adjust keyword density and update the list of related terms. Search trends and intent change over time, and updating content maintains its relevance.
   
6. Measuring results: uses SEO analysis tools to monitor traffic, ranking and bounce rate. This data will allow you to identify areas for improvement and continuously optimize your strategy.
   
   

Applying these steps to each article on your blog helps build thematic authority and improve visibility in search results.

Are LSI keywords an obsolete ranking factor?

For years it has been claimed that LSI keywords directly influenced ranking. However, Google representatives such as John Mueller have clarified that there are no “LSI keywords” and that their use has no effect on ranking. LSI technology was designed to analyze small sets of documents and is not adapted to the scale of the modern web.

This doesn't mean that you should ignore semantic words; on the contrary, current algorithms are based on language models that understand the context and intent of the user. Focusing on creating quality content, satisfying search intent and offering a good user experience is more important than pursuing a supposed LSI label. Instead of obsessing over a non-existent ranking factor, focus on building thematic authority and using related terms naturally.

Checklist for semantic content optimization

Here's a practical list you can follow to optimize your content with semantic keywords:

• Define the intention: identify what question or problem your content answers and what the user's needs are.
  
• Research semantic keywords: use suggestions from Google, Autocomplete, tools such as LSIGraph, Ahrefs, Semrush or Keyword Everywhere to create a varied list.
  
• Create a header structure: organize your text with titles (H2) and subtitles (H3) that include variations of your terms.
  
• Integrate terms naturally: insert semantic words into the text without forcing. If a word doesn't fit, it's best not to use it.
  
• Optimize on-page elements: incorporate related words into meta descriptions, tags Alt and internal links.
  
• Update your content: periodically review if related queries have changed and adapt your content to remain relevant.
  
• Measure and Adjust: monitor the performance of your pages and adjust the strategy based on traffic and conversion data.
  
  

Following this list will help you ensure that your texts are aligned with semantic SEO best practices.

Relationship between Google BERT and LSI keywords

The BERT (Bidirectional Encoder Representations from Transformers) algorithm represents a big leap compared to traditional indexing models. Instead of analyzing individual word strings, BERT uses neural networks and deep learning to understand natural language. Your goal is to understand the context of words by looking at those that come before and after, allowing you to better interpret complex queries.

BERT does not focus on analyzing keywords in a document, but on deciphering what users want to say in their searches. This contextual understanding eliminates the need to force unnatural phrases to position. In practice, this means that writing clearly and naturally and covering a topic well with related terms is the best strategy.

In addition, other technologies such as MUM and Google's AI Overviews go beyond simple keyword matching and prioritize user intent. Content that answers latent questions or offers added value is more likely to appear in AI-generated answers. Therefore, even though the term LSI is obsolete, a semantic and context-oriented approach is essential in the era of BERT and MUM.

SEO strategies with LSI keywords for beginners

For those who are new to SEO, integrating semantic words may seem complex, but the following strategies will help you get started:

1. Understand search intent: classify your user queries as informational, navigational, transactional or investigative and adapt the content to each intention.
   
2. It combines long‑tail and semantic terms: use long-tail phrases to capture specific niches and add related words to broaden the context.
   
3. Create content clusters: develops several interconnected articles that address different aspects of a topic. Use internal links with semantic anchor text to guide readers and engines.
   
4. Optimizes for E‑E‑A‑T: demonstrates experience and authority through reliable data, case studies and source citations; this influences more than repeating keywords.
   
5. Leverage AI responsibly: AI-based tools can suggest keywords and structure content, but they must be used with human supervision to meet quality standards.
   
6. Adapt to the evolution of the SERPs: with AI Overviews taking up space on the results pages, focus on creating content that answers complex questions and offers added value.
   
   

Applying these strategies will allow you to build a solid foundation in semantic SEO and prepare for constant algorithm changes.

SEO case study: increasing traffic with semantic keywords

A recent example shows how the intelligent use of semantic keywords can multiply organic traffic. At the beginning of 2025, a sustainable fashion boutique in Paris barely reached the third page of Google and its organic traffic was stagnant. After implementing AI-based SEO tools and focusing on predictive keywords and long-tail queries, the boutique's organic traffic increased 900% in six months. The company positioned itself for searches such as “ethical linen dresses near me” and stopped relying on paid campaigns, demonstrating that the combination of semantic terms and automated on-page optimization can generate surprising results.

This case highlights how small businesses can take advantage of AI-driven SEO trends to compete with big brands and that a focus on semantic keywords remains essential. Another example is that of a Lyon bakery, which produced 50 items with AI and pointed to local terms, achieving a 40% increase in local visibility. These stories show that strategies based on semantic understanding and advanced tools can have a real impact on traffic and visibility.

Frequently Asked Questions (FAQ)

Are LSI keywords the same as synonyms?

No. LSI keywords include related terms that share context with the main word, but are not exact synonyms. For example, for digital marketing The words “SEO” or “online advertising” are not synonymous, but they are related.

How many semantic words should I include in an article?

There is no fixed number. The important thing is that the words are integrated naturally into the text. Insert related terms when they add value and help clarify the topic; avoiding repeating the main word excessively prevents penalties.

Does Google penalize the use of LSI words?

Google does not penalize the use of semantic words; on the contrary, it values that a content covers a topic in an exhaustive way. What penalizes is the excessive or forced use of a keyword (keyword stuffing). In addition, Google has confirmed that there is no ranking factor called “LSI keywords”.

Do I need paid tools to find LSI words?

Not necessarily. You can start with free options like suggestions from Google, Google Keyword Planner, or Keyword Everywhere. However, payment tools like Ahrefs or Semrush offer deeper analysis and competitive data.

Are the words LSI still useful in 2025?

The term LSI is outdated and Google doesn't use that technology in its algorithm. Even so, using semantic keywords is still crucial for language models to better understand your content. In 2025, focusing on user intent, thematic relevance and reading experience is more important than pursuing “LSI keywords” as a ranking factor.

This guide demonstrates that, even though the original concept of LSI is outdated, semantic optimization remains at the core of modern SEO. Search engines have evolved into language models capable of understanding context and intent, so the combination of semantic keywords, quality content and attention to the user experience is the surest route to position in 2025 and in the future.