Meta Keywords
Meta keywords are a <meta> tag option that could be used to give more information to search engines on what a page is about.
A <meta> tag defines what different types of metadata are about in an HTML document. These meta tags can be found in the source pages of a website, which is what search engine crawlers scan to determine what a page is about.
A meta keywords element was placed in the Head section of the HTML of your webpage, and looked like this:
	<meta name="keywords" content="Keyword1, Keyword2, Keyword3">
Meta Keywords

Meta keywords are considered as relevant by search engines only in a few cases. Google does not use the keywords listed in the meta area of a website for ranking. Even Yahoo and Bing use them only to a limited extent for the hierarchy of search results. In the latter, this information is only one of many factors that determine the order of the search results.

Optimized meta keywords are listed below :

Use a maximum of 10 to 16 meta keywords for a single page.

Use a comma to separate the meta keywords.

Don't repeat any meta keyword or phrase.

Incorporate most important words at the beginning of your meta keyword list.

They should be specific and relevant to the page, i.e. they should accurately reflect what you are talking about on the page.