What are LSI keywords and why do they matter?

What are LSI keywords and why do they matter?

Posted by Callum Sharp
Picture of Callum Sharp
on 18 December 2019

Let’s talk about latent semantic indexing for a moment.

Google for dummies: A quick catch-up

Okay, I want to start at the beginning for those who are new to SEO.

Google is a machine that needs to read and interpret massive amounts of text correctly so it can match a searcher’s query with useful, relevant and accessible information.

But a machine trying to interpret language isn’t all that simple. ‘Burger’ and ‘king’, for example, have two very different meanings, and put together, they mean something else entirely.

To understand what someone is writing about on a website page, then, Google must consider latent semantic indexing.

Before LSI keywords there was keyword stuffing…

Back in the early days of Google, a crawler would scan a website page, find the most popular word, and then index that content against that keyword.

If a blog post had the word ‘coffee’ in it 100 times, for example, Google would think that your blog post is about coffee.

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Unsurprisingly, this led to lots of keyword stuffing. Many companies would write the keyword ‘coffee’ many times over and hide it in the source code of a page. After all, the more times a keyword was used, the more prominent that content was to Google.

But times have changed…

How does Google use keywords today?

Today, Google is a smorgasbord of machine learning and artificial intelligence algorithms that can interpret and understand text almost as well as any human. And when a Googlebot scans a webpage, it no longer looks for a singular word.

Instead, Google looks for words that relate to the topic, so that it can build a more targeted picture.

If we’re writing about coffee, for example, we might use words like ‘beans’, ‘roasting’ and ‘filter’.

Google will read these words, interpret them, and then work out what you’re specifically talking about, and for what keywords your content should be indexed.

LSI keywords aren’t necessarily synonyms

Let’s clear something up. LSI keywords aren’t synonyms, they’re related terms to a topic.

‘Cup of joe’ is a synonym for the term ‘coffee’, and while synonyms are valuable to your SEO efforts (read this), they don’t help Google understand the specifics of your content.

LSI keywords, however, do.

LSI keywords and SEO

If you take anything away from this blog, let it be this: You have no control over what keywords your content indexes for on Google. No control.

Yes, you can do your keyword research, and you can use LSI keywords and synonym keywords to your hearts content. But, ultimately, Google has the final say.

For example, this blog post on tone of voice is indexing for these keywords:Indexing for tone of voice blog 1But it’s also indexing for these keywords:Indexing for tone of voice blog 2Not quite what we were shooting for…

By inserting LSI keywords into your blog post, you can help Google connect the dots of your text more quickly. Then, it can accurately index your content against the right keywords. 

The real question is: what specifically do you want to say? We’ll leave that one up to you.

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Got any questions about this? Feel free to leave us a message.

See also: seo guide

Related service: SEO