As suggested by the name itself, primary keywords are the top-ranking words in the search engine results, perhaps the most important set of words among the content of a website.
They are the type of keywords that are included in the titles, headings, and subheadings; used to highlight the main content of a website to make the process of optimization easy and convenient.
These keywords are determined on the basis of search volumes, meaning how popular they are in relevance with the type of content people are searching online results and how much they are related to the type of content that a website is publishing.
In simple terms, they can be categorized as highly specified words instead of universally generalized phrases that hold different meanings and are used for multipurpose.
The keywords are used by the search engines to put one type of content into a single category, the more keywords are searched by the user to find a specific type of content gives an idea to they about the phrases that are most popular in relation to it.
In that case, you can be assured that the primary keywords are the most looked after on the internet. Apart from the primary keywords, there are secondary and tertiary keywords as well which help in simplifying the Search Engine Optimization.
Clearly, the blend of all three types of keywords is a good way of ranking higher but the primary concern should always be the most popular ones.
The reason you need to be careful and precise with the primary keywords is they constitute the outline of the main content of a website and should be used as the structure on which your content is built.
They also help in constructing a logical Meta Description. This way, search engines get to know that all the data on your website is correlated, as it should be, and excellence in management is also indirectly highlighted.
Leaving a positive impression of the quality of your website as a whole. The use of semantics in keywords also increases the chances of your content coming on top if a relevant key phrase is searched that is even indirectly related to your content.
When you search for something on a search engine, the results come out within a pattern in which the SEO Meta description is at the top followed by the URL with Meta Description Blurb at the bottom.