The Importance Of LSI Keywords In SEO

Tuesday, 11 January 2022 | 11 minutes read

The Importance of LSI keywords in SEO Years ago, search engine optimisation professionals only thought about one keyword when they wanted to rank a web page. Nowadays, it is vital to create excellent content, which is not possible without context.

Keep in mind that 15% of daily searches are brand new terms that the individual never used in the past. Trillions of web searches happen every single year, so we do have more than we can imagine.

LSI keywords started to be relevant in the SEO industry because Google needed a way to understand the pages indexed. The use of these keywords has some pretty positive results in the industry. You want to use them in the content you create to boost contextuality while improving search visibility.

The problem is most people (including many SEO professionals) do not properly understand LSI keywords and what they actually are. Let’s discuss them and understand how they are important in SEO. We will talk about:

  • What LSI keywords are
  • Whether or not search engines use them
  • How to find LSI keywords
  • How (LSI) latent semantic indexing influences rankings
  • Advantages of using related words and phrases in your content
  • How to use LSI keywords

What Is An LSI Keyword?

What is an LSI keyword Here’s an interesting thing that few know. Google mentioned LSI keywords and how important they are ever since 2015. However, the search engine giant did not really explain how these are used and how they impact rankings.

LSI means “Latent Semantic Indexing”.

It is practically a program run on a computer that learns synonyms based on the text's context analyzed. Mathematical techniques are utilized to find a relationship between concepts and words.

When looking strictly at search engine optimisation, an LSI keyword is a search term closely related to the money keyword you target. It supports the content and adds context. This makes it easier for the search engine and the user to understand the content.

As an example, let’s say our main keyword is “studio microphones”. Some related LSI keywords are:

  • Why use studio microphones
  • Best studio microphones
  • Are studio microphones better than home microphones
  • Are studio microphones affected by sound
  • Home microphones

All of these phrases can accompany the keyword you want to rank for.

Are LSI Keywords Just Synonyms?

Some of the LSI keywords are synonyms. However, not all synonyms can be LSI keywords. Most LSI keywords are phrases and words that are related to the keyword you want to optimise for. This means that synonyms will help on-page SEO, although you should never see synonyms as LSI keywords.

For instance, one synonym for “skirt” is “perimeter”. However, if you use the keyword when you talk about fashion, it would be useless to see the use of the word perimeter. Some LSI keywords you could use are summer, short skirt, and denim skirt.

Understand LSI keywords and the difference when comparing with synonyms by going to Google and performing a search.

Screenshot of Google search

Those above are LSI keywords.

Is Google Using LSI Keywords?

Is Google Using LSI Keywords Latent semantic indexing does seem to solve problems related to understanding content, so it is completely normal to think that Google utilizes the technology.

We also see clear examples of the fact that Google understands synonyms:

Screenshot of Google search

Even polysemy is understood.

However, the truth is that Google most likely does not use LSI technology. People from Google said this, and we can also highlight the following two reasons why the statement is true:

LSI Is Old
Latent semantic indexing appeared during the eighties. Because of this, it was not meant to be used with large documents. As a result, Google developed a technology that is more scalable and better. Google practically uses RankBrain, which is a system based on word vector. It can be used on the internet, scales better, and is modern. Learn more about this by reading about Word2vec, which is a natural language processing technique.
LSI Is Patented
Bell Communications Research patented Latent Semantic Indexing in the year 1989. Eventually, one of the technology’s co-inventors, Susan Dumais, joined the Microsoft team to work on search technology innovations. To put it as simple as possible, Google does index different meanings for words. However, the use of the term “LSI” can be misleading. In SEO, it is just a term adopted to better identify a technology that takes content into account. You can say that you find LSI keywords to use to rank higher in search engines, but in reality, the technology identifies words and phrases naturally used by people and search engines use it to better understand context.

Advantages And Disadvantages Of Using LSI Keywords

Advantages And Disadvantages Of Using LSI Keywords As always with anything related to SEO, there can be advantages and disadvantages of doing something. This applies when you find LSI keywords because you cannot blindly use them and expect higher rankings in search results. Use these related keywords only when it makes sense, with the following in the back of your mind.


Google now has a very complex ranking algorithm, one that factors in context. If you incorporate LSI keywords, you automatically boost content contextuality. This offers some clear search engine optimisation benefits:

  • Search ranking is boosted– Because the search engine better understands text when LSI terms are added, your pages are boosted in rankings.
  • More traffic– As you use related words, more people will find the content you create. You end up with more traffic as searchers use related words.
  • Improved content relevance – It becomes easier to avoid keyword stuffing and improve the quality of the text.


There are no real disadvantages to using LSI keywords. However, there are some limitations you need to be aware of, like:

  • LSI does not consider word order and automatically disposes of prepositions and conjunctions.
  • Irony and underlying ideas cannot be recognized.
  • Words are considered to have a single meaning.

Fortunately, Google uses much more advanced technology to present search results. The use of an appropriate LSI keyword can only enhance the content, if used right, of course, alongside the target keyword.

How Latent Semantic Indexing Keywords Affect SEO

How Latent Semantic Indexing Keywords Affect SEO When SEO started to develop, Google spiders scanned websites as they were crawling from a link to the next. There was no list of LSI keywords that could have been used. Only keywords were analyzed to identify the topic of the page. As an example, when the title of the article was “X Tips To Create Email Marketing Strategies”, Google would determine that the topic was “email marketing strategies” as this was the phrase used in some key parts of the page, like:

  • Headings
  • Image ALT text
  • Title Tag
  • Content

After Google updated the algorithm to include its own LSI technology, various SEO improvements appeared. Let's just say that the LSI keywords Google algorithm utilised right now (nobody really knows what the name of the technology is) is very advanced. It identifies much more than the target keyword and allows Google to gain huge advantages, like:

Pages Are Understood Better

Google no longer scans an article to identify the main keyword. It now scans everything to learn about related keywords, like “audience”, “email marketing list”, “newsletter”, “email tools”, “conversion rates”, and more. Latent semantic indexing is used to understand the content. This is possible at a level that goes much deeper than just identifying the keywords that appear more often.

In content marketing, creating content that can easily be understood by the audience is vital. If this does not happen, the campaign is a fail. Google understands this and does all it can to properly understand the intent behind every single search query.

Pages Are Contextually Read

Google's algorithm is much more capable of reading the page in a similar way a human does. Also, it can categorize keywords based on a determined context. It is easier for Google to differentiate between the words used actively. This is even possible with tiny details. It is possible to analyse a list of related terms and create a results page filled with relevant results.

Search Results Are More Relevant

Google declared that it now manages to identify the frequently occurring words to help crawlers understand topics when scanning. Since the categorization is more accurate, the results listed are also more relevant.

User Experience Counts

At the end of the day, this has a huge impact on user experience. You create a piece of content that has a goal, like making a sale, or generating income through AdSense. Google and other search engines manage to understand the content, categorise it properly, and take much more into account than just words.

How To Find LSI Keywords To Use

How To Find LSI Keywords To Use Now that we understand the advantages of using LSI keywords in search engine optimisation, it is time to talk about finding such phrases to use. Fortunately, this is not at all difficult because there are different tools that you can use.

Google Autocomplete

Screenshot of Google autocomplete

The instant search feature offered by Google is the simplest possible way to find some keywords related to the one you want to optimise. Simply type the target keyword inside the search box. After, you receive a list of predictions. Basically, Google tries to guess what you want to write. The suggestions are all LSI keywords you can use.

Google Related Searches

Google related searches example for weight loss term

Type the keyword and perform a keyword search. Then, move all the way down and look for “Related Searches”. The terms listed there are also LSI keywords you could use.

People Also Ask

Example of People Also Ask Google Feature

This is another free resource you have access to. The box appears when you search for a keyword, and Google determines some related questions people ask. Find those that are relevant and include them in your content to create something better, an article that answers actual people question.

LSI Graph

LSI Graph search for weight loss related keywords

This free generator gives you free LSI keywords very fast. You just type in the money keyword, and you receive a large list of phrases or keywords to consider. You even receive a list of the best performing content right now based on your keyword so you can get extra inspiration.


If you need another tool to look for semantically related phrases, Serpstat should be considered.

Serpstat weight loss search results

As with the other tools before, you just need to enter the main keyword, and you will be offered some suggestions. The great advantage of using this tool is you can choose what local targeting to use. For instance, if you need to research in Australia, you pick from the list.

As expected, several other wonderful SEO tools exist out there, and they can give you access to lists of LSI keywords. However, you can have the best list possible and still not use it properly. This is why we should discuss how to use these keywords.

How To Use LSI Keywords

How To Use LSI Keywords After you create your lists of LSI keywords that could help take your content to the next level, it is time to use them properly. Here is how you do exactly that.

Choose The Appropriate LSI Keywords For The Topic You Cover

Even before you think about how LSI keywords can be incorporated, you have to identify those phrases and words suited according to the topic. As an example, when you target a keyword like “weight loss”, you will find incredibly useful options like:

  • Weight loss advice
  • Weight loss misconceptions
  • How to lose weight
  • Adelle weight loss
  • Weight loss exercise
  • Weight loss tips
  • Can you lose weight during pregnancy
  • Weight loss after pregnancy
  • Etc

Obviously, all of these can be good, but you cannot incorporate them in a single article unless you want to write everything about weight loss, which would be a book, not an article.

Analyze Monthly Search Estimate

Monthly search estimate is usually presented in tools like the above mentioned LSI Graph as volume. It is essential to look at this because it shows you if it is worth targeting the specific keyword or not. If you only see a very low volume, it is best just to ignore it.

Keep in mind that you should know the monthly search estimate for all the LSI keywords you identify. You will see many phrases that simply do not match the topic you want to discuss in your article. In this case, if the monthly search estimate is high, write it down since you might want to use it in your next piece of wonderful content.

Adding The LSI Keywords

The LSI keywords that are the most relevant and related to the main keyword should be added to the same areas where you add that main keyword. This includes:

  • Headings, including H1, H2, and H3
  • Body text
  • Meta description
  • Meta title
  • Image alt tags

It would be best if you spread the related phrases and words throughout the post. The goal is to create content that sounds natural.

Create A Great User Experience

One of the worst things you could do is use LSI keywords way too much in the content you create. These are not keywords, but overusing is really common. When you do this, it is very easy to be penalised.

Simply put, you need to include enough of the identified LSI keywords to make the page’s context clear for Google, all without ruining the reader's experience.

When you try to do this effectively, related keywords should be added while the content remains natural-sounding, very easy to follow, and cohesive. If you manage to do this, you can improve the experience of the visitor.

Never underestimate the importance of user experience. When people use Google Search and they reach your blog post, they want to find something. Content marketing is all about creating the content that people want to see. This is why a list of related words will help. However, semantic keywords are never enough if you do not also look at other elements, like page load speed, having unique web pages, an appropriate number of words to go in-depth with the content, and properly covering the overall topic.

Final Thoughts

Final Thoughts Latent semantic indexing became a term we use to describe the related words and phrases we use to enrich the quality of the content we create. Although many other terms are used and might be more accurate, like "natural language processing", for the sake of argument, let's just say that you use LSI keywords to enrich the user's experience and make Google understand more about what you write.

The big problem is that creating content that is fully enriched with LSI keywords is not simple. Search engines cannot be tricked by just using all the related words and phrases you find. It is very easy to overdo it and get drawn in by volume when you find LSI keywords. You will see many different related words, not just two different words when you use LSI tools. Find related content and use it properly.

Some General Things To Remember To Improve Your SEO With LSI Related Terms

Enhance your results in search engines when you find LSI keywords and use them properly by respecting some very simple tips:

  • Never go overboard with related keywords and synonyms.
  • Try to write exactly how you speak. Do not blindly add keywords in your content in a way that is not natural.
  • Try to use a strict fixed ratio of the related words compared to the rest of your content (for instance, use one of the related terms every 200 to 300 words).
  • Use an LSI keyword generator to improve the content of your page. Do it when you perform keyword research.
  • Find related words but only use them when they are relevant.

Latent semantic indexing (LSI) keywords are not related searches or just semantic keywords. You add LSI keywords as related words that enhance the content. This will take time to master. However, if you manage to do it, those words and phrases you add will allow search engines to better understand your content. Your target keyword will be ranked higher, and you might get some extra rankings in search results with the latent semantic indexing keywords.


Arthur Choi

Arthur Choi

SEO Strategist

70% technical SEO, 30% offsite optimisation. Loves to strategise and build organic SEO campaigns for plumbers, excavators and e-commerce clients.


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