What is keyword density ?

hey friends please suggest me,
What is keyword density ?

In search engine optimization (SEO) keyword density is the measurement in percentage of the number of times a particular keyword or phrase appears compared to the total number of words in a page.

Keyword density is another most important techniques for promote website in google. you should keep 2-3 % keyword density.

Keyword density is the percentage of times a keyword or phrase appears on a web page compared to the total number of words on the page. In the context of search engine optimization keyword density can be used as a factor in determining whether a web page is relevant to a specified keyword or keyword phrase.

Keyword density is the percentage of the number of times a keyword appears on a page divided by the total number of words in that page.