What are LSI keywords? Everyone seems to be talking about them.
And for good reason.
It's the way search engines decide which pages are relevant to a given search query.
In this article I show you everything you need to know about LSI keywords and how to use them to improve your SEO:
- What are LSI keywords?
- Why does Google use them?
- How they can improve your ranking
- Where to find them
- Three ways to easily add LSI keywords to your articles
Before We Go Any Further, Here Are Some Definitions
Latent semantic indexing (LSI) is a mathematical technique that detects the way words cluster together in predictable patterns. Search engines use these patterns to understand context.
LSI keywords are words semantically related to your main keyword. They are words that are often found together with your keyword they share the same context. For example 'apple' and 'itunes' are LSI keywords.
Here are some examples of how LSI works.
Let’s say your page or blog post is about Cars (thanks to Nikolay for this example).
You could be writing about any of the following 5 meanings of ‘Cars’:
- Cars the vehicle
- Cars the animated Disney movie
- CARS, the Canadian Association for Rally Sports
- CARs, the Canadian Aviation Regulations
- (The) Cars, the American 1970s music band
How does Google know which meaning of ‘Cars’ is relevant for your page?
Google will be looking for LSI keywords on your page to decide which is the correct meaning:
- If it finds the words: 'vehicle', 'used', 'new', 'buy', 'sell', 'dealers', 'repair', your page is probably about cars, the vehicle
- If it finds the words: 'film', 'movie', 'produced by', 'directed and co-written by', 'motion picture', 'Walt Disney', your page is most likely about Cars, the movie
- If it finds the words: 'association', 'rally', 'sport', 'championship', 'Canadian', your page is probably about CARS, the Canadian Association for Rally Sports
- If it finds the words: 'aviation', 'regulations', 'administration', 'aerial', 'aerodromes', 'airports', your page is most likely about CARS, the Canadian Aviation Regulations
Here’s another example (thanks to Fedingo Marketing for this one):
Let’s say your page or blog post is about Apple.
How does Google know if you’re referring to the fruit or the company?
It looks for LSI keywords:
- If your page contains the words: 'baked apples', 'red apple', 'green apple', 'apple nutrition', 'fuji apples', 'honeycrisp apple', 'eating apple', your page is probably about apples, the fruit
- If your page contains the words: 'itunes', 'apple hulu', 'apple news', 'apple stores', 'apple iphone 5', 'apple new ipad', 'apple stock price', 'discount computers', your page is most likely about apple computers
LSI Keywords in Action: An Example From The Movies
Do you remember the 1987 movie 'Fatal Attraction'?
Let's say you're talking about it with a friend and neither of you can remember the title of the movie or who was in it. All you can remember is that someone boiled a rabbit.
So you go to Google and type in 'movie where someone boiled a rabbit'.
Bingo! Google finds what you're looking for:
How did Google do that?
Latent Semantic Indexing.
The Google algorithm has learned that the words 'rabbit', 'boiled', and 'movie' cluster together in a predictable pattern associated with the movie 'Fatal Attraction'.
So why did Google start using LSI keywords?
Why Does Google Use LSI Keywords?
There was a time when the only measure Google had for relevancy of a page to a given search query was keyword density.
As we all know, keyword density was horribly abused and spammed.
So Google moved away from keyword density and began looking at LSI keywords.
The reasoning was this:
A legitimate page about ‘Apple computers’ will likely contain a host of other words that are related to Apple computers (such as 'apple stores', 'apple iphone 5', 'apple new ipad', 'apple stock price', 'discount computers').
On the other hand, a keyword-stuffed page about ‘Apple computers’ will probably just contain that one keyword.
So LSI keywords provided Google with a way to sort the sheep from the goats.
LSI Keywords and Searcher Intent
But there’s another reason Google started using LSI keywords.
Latent Semantic Indexing helps Google to better understand the meaning of a search query and the meaning of a web page.
As I mentioned above, certain words cluster together in predictable patterns. Understanding these patterns allows Google to understand the meaning behind a search query.
And that allows Google to improve the match between what people search for and what they find in the search results.
Hummingbird and Semantic Keywords
In August of 2013 Google introduced the Hummingbird algorithm, sometimes called the semantic algorithm.
The Hummingbird algorithm focuses on synonyms and improves Google’s ability to understand the context of a web page.
Hummingbird is particularly interested in searcher intent.
Whereas previous algorithms focused on individual words in a search query, Hummingbird looks at each word within the context of the whole search query.
In other words, the Hummingbird algorithm is trying to understand meaning – it helps Google match user intent with search results.
But how does this help you rank higher in the search results?
3 Ways To Use LSI Words To Improve Your Ranking
Here are three ways LSI words will improve your SEO:
Total Context vs. Keyword Density
Google now looks at total context rather than keyword density. LSI words will give more context to your article. This means your page will rank higher for your main keyword because Google better understands the context of your page.
You Reached Your Limit for Keyword Density
Let’s say you’ve reached the limit for keyword density on your page – anymore repetitions of your keyword and you risk a Google penalty.
With LSI keywords, you can safely keep adding closely related keywords.
Get Found for Keyword Variations
LSI keywords are closely related to your main keyword - they're 'keyword variations'.
That means your page is going to come up in the search results for your main keyword as well as for those keyword variations.
Where To Find LSI Keywords?
The best place to find LSI keywords is in Google. That way, you know your LSI words are recognized by Google as being semantically related to your main keyword.
Just type in your main keyword into Google and look for LSI keywords in the SERP snippets.
Let's say you're writing an article about 'tendonitis'. Here are some LSI words for 'tendonitis' that you can extract from the Page #1 search results:
That exercise gave me 19 LSI keywords for tendonitis. And I only looked at 5 of the SERP snippets in the search results.
Google Auto Suggest
As soon as you start typing a search query into Google, Google's Auto Suggest function suggests a number of related terms that people also search for.
These are LSI words - Google's algorithm has identified them as words that cluster together with your search term in predictable patterns.
Here are the Google Auto Suggest terms for 'tendonitis':
In this instance, I already have these words from the previous exercise. But what if I click on 'tendonitis wrist':
That gives me some additional LSI words. You can keep drilling down through the Auto Suggest entries and find more and more LSI keywords.
Google's 'Searches Related To'
Yet another way to extract LSI keywords from Google Search is to look at 'Searches Related To' at the foot of the SERPs page:
LSIGraph is a free tool for generating LSI keywords.
Just enter your main keyword:
Then scroll through the results for more LSI keywords:
As with the previous tool, just enter your seed word and hit 'search'. This tool returns a massive list of over 1,800 keywords related to 'tendonitis'':
This is another great tool for finding LSI keywords. In my case, it gives me over 300 of them:
Three Easy Ways to Add LSI Keywords to Your Blog Post
Adding LSI keywords to your article isn't always easy, especially if you have to re-write parts of your article to fit the new words in.
But here are three super-easy ways to add LSI words to your blog post without having to re-write anything:
1. Add a Further Reading Panel Under Each Section
Under each section of your article, add a 'Further Reading' panel that lists three to five articles related to the topic of that section.
These articles will inevitably contain LSI keywords in their titles. Let's say I have a section in my article with the heading 'Cures for Tendonitis'.
I could add a 'Further Reading' panel at the end of that section, like this:
With that single 'Further Reading' panel, I've just added 10 LSI keywords to my page.
2. Add a Related Articles Panel
If you've written other articles on the same general topic, you can link to them in a 'Related Articles' panel. The titles of these articles will almost certainly contain LSI keywords.
Here's an example:
The main article targets the keyword 'domain authority'. This 'Related Articles' panel contains five LSI words related to 'domain authority'.
3. Embed a Tweet
Go to Twitter's Advanced Search and type in the your main keyword in the field labelled 'All of these words':
Choose a tweet that has a lot of text - it should contain some valuable LSI keywords. Then grab the embed code and embed it in your article:
This is also a great way to add an image to your article (two birds with one stone).
LSI keywords are at the heart of Google's new approach to understanding content. That's why it's important to be aware of them as you optimize your blog posts for SEO.
By researching the LSI keywords associated with your main keyword, you'll get a better grasp of the geography of your topic. And that will help you write an article with high topical authority.