Gangly

Sorry to bug you guys, but what does it mean when people say "shrouding" or to "unshroud" a valve, and when would you do it?

Colonel

Having a valve shrouded means to have it's opening so close to something (like the cylinder wall) that flow is impeded.

This is a very simple explanation and I'm not at all sure if it's complete. Someone please feel free to expound upon this if need be.