Other Terms

Keyword Density

Keyword density is a metric in SEO, the percentage of a specific keyword or phrase appearing in the text of a page relative to the total word count. This number, measured in %, helps Google to understand the relevance of a page. 1-2% is most frequently mentioned as the target range.
You get the density by dividing the number of times the targeted keyword appears by the total number of words on the page and then multiplying the result by 100 to get a percentage.

10 years ago, keyword density was a significant ranking factor. The more frequently a keyword appeared, the more relevant the page was to the topic. 

However, today Google is way more sophisticated, and it uses a variety of factors to assess relevance and quality. Not just a number. Excessive repetition of keywords, aka keyword stuffing, now will negatively impact SEO. Google sees it as manipulative and detracting from the user experience.

A balanced keyword density shows Google that the content is relevant to a specific topic without overdoing it. There is no exact “perfect” percentage, though most experts believe that 1-2 keywords per 100 total words is the way to go.
“The more, the better” doesn’t work now. Depending on user intent, the nature of the page, and the specifics of your niche, not mentioning the keyword directly at all can be the best way to go. Google praises naturality, and you can see pages with a keyword density of zero ranking among the first results. 

Since being natural is #1 priority, this is what you should keep in mind:
While it’s an important aspect, the primary focus should always be creating content that’s useful and engaging. Especially since Google or any other search engine has never provided any specific number for optimal keyword density.