What is an Authority Site?

What is an Authority Site? I want to know definition of Authority Site and is there a Authority Site which provides free services? eg: http://www.wikipedia.org/

 

You won't find two people who will define it the same way - it's not a title that has an offiicial recognition, it's just what people call a site that they consider the top one in their field.

 

http://www.seobook.com/glossary/

http://www.seomoz.org/blog/smwc-and-other-essential-seo-jargon

 

* There is no standard use or definition for “authority site”, “authority link”, etc.
* There is no metric for determining the amount of supposed authority a site or page may possess.
* You cannot easily determine whether a supposed authority site’s links are passing value.

Instead: You will find more resource sites than supposed “authority” sites (because anyone can be a resource).

Source: Seo-Theory

 

possibly one that has sitelinks on Google

 

Sites with Google Site Links are considered authority sites by Google. That's for sure.

 

seobook.com,

 

I am Agree with Zexy. Site that appears with Google site links is count as Authority sites.