Below is the Meta tag of the Example Document,
Good and Safe Keyword Density ratio revealed for SEO. Keep your Keyword ratio between this then your website do well in search
For well Optimized Meta Description tag the selected Keyword for the Page is Keyword ratioHow it's works
Here the chosen Keyword for the Page is Key Phrase Word but the tag doesn't optimize for the Keyword
So this tool analyzes your Meta Description tag for various Keywords and gives the report about how it's optimized for the particular Key phrase. Rather Using Key phrase is better than Keyword in the tag and also it's makes better chance in front of SERP in various keywords.
Latest modern Search Engines like Google using some synonyms terms that matched to our word so use synonyms of the Keyword in this tag. Also It's changes the Meta tags with the inner page contents. So keep it relative to your content.Updated on Sep 03, 2015