Hi all. I’m brand new to the HubSpot Community, and to SEO! As a beginner, I still have much to learn so I’ll throw one of those “keeps me awake at night” questions. 
What’s the difference between a related keyphrase and a keyphrase synonym? Can Google make a distinction between related/synonym keyphrases and a focus keyphrase, or do they both “equally count” towards rankings?
Hi @HSeeley,
welcome to the Communtiy!
I wanted to tag in a couple of subject matter experts to see if they can tell us more about this topic:
hi @danmoyle, @GeorgeBThomas, @Katherinegavin1, could you help with this question? Thank you! 
Cheers
Mia, Community Team
Hey there @HSeeley! Welcome to the HubSpot Community 
Thank you for the tag @MiaSrebrnjak!
Here are two resources I found on this subject, outside of HubSpot. This tells me that 1) testing is key and 2) variation is important.
I’d also share these two HubSpot resources to consider when thinking about evolving SEO:
As for Google’s distinction and where importance is placed, from what I’ve seen it’s hard to know exactly without testing your specific use case continuously. I would recommend using them both and deciding what’s performing better.
Thank you for sharing such great resources! Lots of food for thought here.. 
Hey @HSeeley this is actually a FANTASTIC question when it comes to keyword research, content writing, and on-page optimizations.
Simply put the difference between a related keyphrase (also known as LSI Keywords) and synonyms are their relation to the original keyword.
A related keyphrase is a term that doesn’t have the same meaning, but more of a complimentary term for. For example, an LSI keyword for “seasons” would be “fall, summer, spring, winter” as they are related to the word “seasons”.
A synonym would be “cars” and “automobiles”.
Yes, Google is advanced enough to understand them both.
For SEO, LSI keywords are not really a “thing” that is being judged by Google when ranking. According to John Meueller from Google “There’s no such thing as an LSI keyword - anoyone who’s telling you otherwise is mistaken, sorry.”
However, it is best practice to avoid keyword spamming so using synonyms is a better alternative. Plus it will help you rank for more keyword variations when creating content and improve the “reach” of your post by appearing in synonym-related searches.
In terms of using LSI keywords, it just ensures your covering the topic in detail.
Hope this help!
Really appreciate this reply! Thank you for the insight! 
