Automotive Chevrolet Metal

What is the name of this line/hose?
I've heard this line called many different things: purge line, heater core return line, thermostat bypass....I need to know what the name of this part is so that I can replace it. I've included a link to a picture as well. I'm talking about the metal line coming from the right side of the motor and running in front of the motor, connecting in front of the dipstick.
http://media.automotive.com/evox/stilllib/chevrolet/cavalier/2002/2co/50.jpg
the pic is a bit small, but it looks like the high pressure line for the AC.


US $13.00