Definitions for "Keyword Frequency"
A measure that is used to count the number of times a keyword/keyword phrase is repeated in a webpage.
Keyword frequency is the number of times keywords occur in the text on a given page. Search engines want to see more than one repetition of a keyword in your text to make sure it's not an isolated case.
The percentage of the total words found on one page of your web site that are the same word. ie. If Abalone Designs' first page has 100 words and within those 100 words, the word "web" appears 25 times, the keyword frequency for the word "web" is 25%.
Keywords:  prominence, highlighting
Keyword highlighting Keyword prominence