Keyword prominence works on the principle of the location of the given keyword in the HTML source code and the web pages.
It depends on the availability of the word, higher the word in a page more prominence/weight it will have.
Keyword prominence refers to how prominent your keywords are within key elements of your web page. Specifically, how close to the beginning of the page's TITLE tag, heading tags (H1, H2, H3, etc.), and meta DESCRIPTION, your keyword phrase is placed.
Keyword prominence refers to how prominent keywords are within a web page. The general recommendation is to place important keywords at, or near, the start of a web page, sentence, TITLE or META tag.