It is a fantasy adjective that politicians use to distract you from the fact that they have mostly lost the ability or political will to cooperate to do the business of the people. This is because their positions are so solid that unless one party rigs the system (Like Tom DeLay did in Texas) the seats never change hands. Then the pols that get elected are the ones that hold the far end of the spectrum views. Moderates need not apply. If the legislatures didn't control the districts, this wouldn't happen.
This is why I support the Schwarzenegger plan to hand districting over to a panel of retired judges. They don't have anything to gain by carving up districts into funny shapes.
That's what bipartisan means dear.