What does VQ stand for?

What does the VQ stand for on the VQ30DE?
I know 30=3.0 liters D=Dual overhead cams and E=Electronic fuel injection.

But what does VQ mean?

"very quiet" ? hehe...
here is a website I found explains the meaning of Nissan engine codes
http://www.freshalloy.com/site/features/tech/engines/home_codes.shtml

Thanks, But i already knew all this. But, I thought VQ had a meaning, like RB=Racing Breed. Thanks

RB does not stand for race bred

VQ is nothing but a pair of letters that represents the series of engine