What is PR?

[adoptabledomains]

Lately I've seen a new term for rating domains such as "PR3". My assumption is this is "Popularity Rank" and a number? If so, where is this number coming from. If not, what is this new acronym?

Somewhere, I think I missed out on this one.

 

[theparrot]

PR is the Google Page rank.

 

[hotdog_pk]

info:
http://www.google.com/webmasters/4.html