Types of keywords

[SeoDezin]

What are the Primary, Secondary and related keywords in SEO ?

[Ravina97]

A primary keyword, as the name suggests, is a keyword that's used before the other keywords on a web page or in an article.
Therefore, the primary keyword is the most significant keyword on a web page.
In turn, then, the primary keyword should be included in a site’s title and domain also as in its content.
It should be added to the first sentence on the page too.
The primary keyword is important for purposes of SEO because it is used to explain the web page as well as help folks locate the site.

A secondary keyword is used after the primary keyword and isn't needed with relation to SEO.
However, once a secondary keyword is used, the possibilities of attracting extra visitors to your web site are increased.

[harrywood]

I think we can say that short tail keyword is a primary keyword, longtail keyword is a secondary keywords and LSI (latent semantic indexing) Keywords is know as a related keywords.

[RanKumar]

You are sharing the right things about types of keywords, I think there are three types of keywords :- high competition keywords, medium competition keywords and low competition keywords. You can specify primary, short  and LSI keywords among these type of keywords.