Keyword density is the measure that expresses percentage of indexable text words. It can be calculated as a ratio between the number of how many the keyword appears and the total number of words shown on the certain web page.
For example, if a keyword appears 4 times on the webpage with 100 text words, the keyword density is 4 %. This measure should be high enough, not too much. The higher percentage indicates search engine spam and pages can be penalized for keyword stuffing
From Starting Your Own Affiliate ProgramGet Started