heatsink-stock : what does it mean ?

[9lives]

http://www.anandtech.com/showdoc.html?i=1430&p=1

each brand got a (stock)behind, what does it mean?

 

[Vampire]

(stock) indicates that the heatsink was tested with the fan that came stock with the heatsink. The other tests for the same heatsink indicate that the stock fan was removed, and a different fan of the indicated specification was installed.