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How to Find Semantic Keywords (Tools + Tips)

by Claire Broadley
Last Updated: March 4, 2025

Google is continually refining its search algorithms to improve the relevance of search results.

It has changed the way it ranks content to “surface the most helpful information”.

And systems like RankBrain are getting better at understanding content.

As Google raises the bar for publishers, targeting a single keyword is no longer enough to achieve great search engine rankings.

Instead, you’ll need to explore topics in greater depth, and use a much broader range of terms.

That’s where semantic keywords come into their own.

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Topics, Keywords, and EEAT

Google RankBrain is a machine learning system that creates relationships between related terms and phrases.

Think of it like a 3D map where related terms are closely grouped in clusters.

RankBrain processes the language we use to understand what we’re looking for.

(And it’s smart; if it doesn’t know what a phrase means, it’s capable of guessing based on the other terms you’ve used.)

Google has a page on its website that explains their systems in more detail:

“...our systems analyze [the] content to assess whether it contains information that might be relevant to what you are looking for…. After identifying relevant content, our systems aim to prioritize those that seem most helpful. To do this, they identify signals that can help determine which content demonstrates expertise, authoritativeness, and trustworthiness.

In SEO, expertise, authoritativeness, and trustworthiness are the most important signals of “helpful content” - along with the extra ‘E’ in EEAT, experience.

Google wants to reward content written by experts who draw on real-world experience. And this is the kind of content that readers love, too.

That’s because experts are best placed to provide factual information in an easily digestible format. They naturally use related terms to touch on new concepts that the reader will find helpful.

And 72% of marketers say the most effective SEO tactic is publishing high-quality content.

So when you use semantic keywords (sometimes called LSI keywords), you’re proving to RankBrain that you know what you’re talking about. These keywords are a framework for more detailed, rounded content that readers are more likely to bookmark or share.

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Before we move on, remember that semantic keywords are just one part of the story. You need to use them while demonstrating EEAT.

As Marie Haynes says:

“If you are lacking EEAT, I suspect that tweaking your text to look better to vector search will not do much.”

That means you need to build a reputation over time. Just adding keywords to thin content will no longer get results.

How to Find (and Use) Semantic Keywords in Content

Now we understand more about semantic keywords and EEAT, it’s time to look at ways to find and check those keywords.

When experienced writers create content, they naturally branch out into related topics and mention related terms and concepts to support the points they make.

So if you know your stuff, there is a good chance you’re already using semantic keywords.

That being said, I still recommend researching these keywords to ensure you’ve captured everything your reader wants to know. The process helps you to understand their search intent more deeply.

Let’s look at some ways to research semantic keywords.

1. Topic Research Tool

Once you’ve shifted your mindset from ‘single keywords’ to ‘topics’ or ‘concepts’, you’ll understand why the Semrush Topic Research Tool is so powerful.

Instead of looking at data on one keyword, it brings together data on a topic, incorporating data from many different sources like:

  • Search results
  • Keyword metrics
  • Headlines gathered from top-ranking articles
  • Questions about the topic
  • Related searches
  • Trends

This can help you to:

  • Plan a high-quality article, or a group of articles on a topic
  • Verify that you’ve covered a topic in enough detail
  • Quickly understand a topic that's new to you

For example, you can explore different angles when writing about a new product that's trending.

In Semrush, go to the "Content Marketing" section and click "Topic Research" in the sidebar.

Enter your main topic or seed keyword to start.

When the results load, you'll see various Topic Cards. These are all semantically related concepts.

Content Ideas in Topic Research Tool

Each card could become a section in your article, or it could inspire a standalone article that is related to the main keyword.

At the top, I like to use the dropdown to filter by topic efficiency.

Topic efficiency score

I haven’t seen a topic efficiency score in any other SEO tool, but now I refer to it every time I write.

It’s a simple formula that balances search volume and difficulty. High-volume, low-difficulty keywords get a higher score.

In the Topic Research tool, you can also expand any topic card to get:

  • Subtopic volume
  • Ranking difficulty

And on any topic card, you can click "Get ideas on this topic" to drill down into a new set of semantic keywords and topic ideas.

Get topic ideas in Semrush

The Topic Research tool gives you a ton of ways to save and refer to the topics you’ve researched. You can:

  • Add topics to favorites
  • Create a draft with AI
  • Send the task to Trello
  • View as a Mind Map
  • Send it to an SEO Content Template to turn it into a brief

SEO Content Template lists out all the semantic keywords for you.

Semantic keywords in SEO Content Template

Just keep in mind that these terms are picked out from competing articles.

Instead of just adding the term in the text, you’ll need to prove EEAT:

  • Structure your content so that you link the term back to the main topic of the article
  • Provide examples of concepts based on real-world experience
  • Back up your claims with relevant statistics or evidence

You can likely come up with even more if you know the subject matter well.

2. People Also Ask Questions

The People Also Ask section of the search results page shows you related searches.

These questions are a goldmine of semantic keywords that you can use in your content.

Often, you’ll find specific questions that you can use as headings.

Semantic keywords in People Also Ask

When writing content, it always helps to think about what your reader will want to know next. For that, you can also refer to People Also Search For queries in the SERP.

This section is a great way to ‘get inside the head’ of the person who’s searching so you understand their question or problem.

Semantic keywords in People Also Search For

Extracting this information from the SERP can be challenging. To make it easier to organize and export, you can also get question data from the Semrush Keyword Magic Tool.

When you search for your primary keyword or topic, set your filter to “Questions”.

Experiment with the different keyword match types at the top and save specific keywords that are related to your article.

Related questions and metrics

3. Exploding Topics Free Keyword Research Tool

Our free keyword research tool gives you an instant overview of related keywords for any seed keyword. I use this tool when I want to quickly look up a list of related topics as I write.

To look for semantic keywords, just type in your keyword and hit “Find Keywords”.

In this example, I looked up keywords for an article on the best mechanical keyboards. I got helpful ideas for new sections or subtopics like:

  • Wireless
  • Custom
  • Low-profile

Related keywords and metrics

Talking about these semantic keywords in my content would help to improve my article and show that I understand this product well.

If I do this for every article, I’ll increase my topical authority and prove to search engines that I can be trusted to provide accurate information.

Notice that the table provides metrics for each suggestion. I can see:

  • Search volume
  • Keyword difficulty (KD %)
  • Cost-per-click
  • Number of results
  • Search trend

Search trend is great for picking up on trending topics before anyone else notices them.

All of this information is available for free, and you don't need to create a login. Try it right now.

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4. On Page SEO Review

If a page isn't ranking as well as you'd like, it's a good idea to look at exactly what it's ranking for. I compare the top 3 articles to mine to see if I could make mine more helpful.

Optimizing and improving web pages is known as on page SEO. If this is new to you, we have a helpful guide to on page SEO that will help you out.

Semrush has a tool specifically designed to help you improve on page SEO. It checks things like semantic keywords, technical SEO, and user experience for the pages you want to improve.

To set up the On Page SEO checker, you’ll first need to sign up for an account and add your site to a Project. Once that’s done, you can specify the pages you’d like to optimize. You can import them directly from:

I like to provide the exact URL I want to optimize. It takes a few minutes for Semrush to gather optimization ideas.

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You can see that the ideas are split into categories:

  • Strategy
  • Backlinks
  • User experience
  • Technical SEO
  • SERP features
  • Semantic
  • Content

When you review the “Optimization Ideas” tab, you’ll see a breakdown of suggestions in each of these sections.

The “Semantic” section is the one we're interested in today. It provides a list of search terms that your competitors have used. It finds these by comparing your pages with rival domains that are ranking above you in the top 10 Google search results.

This keyword list helps you to quickly consider whether your content is missing sections that might make it more helpful.

You can click “See detailed analysis” to drill down into the list. 

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The metric I use most is the TF-IDF score. It's a measure of the number of times you should use a term on the page. 

Ideally, the figure in the “My” column should be no more than the “Max”, and in line with the “Rivals avg”.

Of course, your own expert judgment should be the deciding factor when expanding content. TD-IDF is a safety net to guard against accidental keyword stuffing.

5. Keyword Strategy Builder

If you spend a long time on keyword research, you may find yourself battling with hundreds of semantic keywords.

(According to the latest SEO statistics, Semrush has more than 25 billion keywords in its database.)

It’s easy to get lost in a spreadsheet, not knowing which ones to pick out. So how do you know your chosen semantic keywords are the right ones?

To make sense of your list, I recommend moving the keywords to the Keyword Strategy Builder.

It’s an AI SEO tool that organizes keywords into topics according to their meaning and the search intent behind them.

In the Strategy Builder chart, you can see the primary topic in the center, marked “Pillar”. This will often be your target keyword. Clustered around it are the subtopics.

Topical overview with pillar pages

This can help you to turn a messy list of semantic keywords into a viable content plan.

In the example below, I switched into the list view. The Keyword Strategy Builder found 233 potential pages for some content on “vegan meat alternatives”.

Using the filters at the top, I can choose a customized plan that’s focused on my goals for the content I’m working on:

  • Best for strategy
  • Easy start
  • Quick conversions
  • More potential traffic

Keyword Strategy Builder filters

“Easy start” keywords would be perfect if I wanted to establish topical authority on a trending topic that I haven’t written about before. 

Many of these ideas are sourced from top ranking pages, so they are a great starting point.

Keyword Strategy Builder results

6. SEO Writing Assistant

Whenever I update content, I always have the goal of expanding the topic coverage in a way that helps my readers.

For this use case, the SEO Writing Assistant is perfect for finding keywords that I missed the first time round.

You can paste in your existing article and get semantic keyword suggestions. This can uncover new concepts and topics.

It also helps you to capture new developments and emerging trends.

Semantic keywords in SEO Writing Assistant

The "Recommended keywords" section is a goldmine of relevant keywords based on the text you're working on.

I’ve tried various alternatives to this tool, including Frase and Surfer SEO. I always come back to Semrush because the tool works inside Google Docs, which is perfect for the way I work.

The SEO Writing Assistant is powerful and will make a ton of suggestions, so here are my golden rules:

  • Ignore semantic keywords that aren’t a natural fit for your content
  • Write ‘around’ the words and phrases to ensure you deliver value

As your articles get longer, you will likely need to add or move headings to support a good user experience.

Web page structure

Remember that the goal is to meet search intent more closely, using these suggestions as prompts or reminders.

7. Google Keyword Planner

Keyword Planner is a free tool that makes it easy to find related terms. It’s designed for businesses that run Google Ads, but you don’t need to pay for ads to use it.

Just log in and click “Discover new keywords” to start.

Discover new semantic keywords in Keyword Planner

You can search for up to 10 keywords at a time and generate a list of related terms.

semantic keywords in Keyword Planner

The Keyword Planner shows you the search volume for the entire group at once. That gives you a good idea of the overall traffic potential.

And, of course, it’s free to use.

If you’d like a deeper dive, we’ve written a full guide on researching keywords in Google Keyword Planner.

Start Researching Semantic Keywords Now

Modern search engines are getting better at rewarding high-quality content that’s packed with EEAT.

The algorithms might not be perfect yet, but there's no going back to the old ways. Google is investing a huge amount of money in giving searchers relevant content on the first try, and it will only improve over time.

Incorporating semantic keywords is a great way to ensure your content meets the needs of searchers and search engines. It can help you to ensure that your content offers information gain and value.

And three of the tools I listed are available with a free Semrush account, so that’s the perfect place to start.

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