Front end bar that streches the lengh of the car, sway bar or stabilizer bar?

What is your question?

I pulled into my driveway yesterday and heard a huge clunk like I hit a piece of ice. There was nothing in the driveway. The next day I heard a rattle coming from the driver's side. My boyfriend looked underneath, turning the wheel as far as it would go, and found that the bar that streches the length of the car snapped and is now hanging loose. Is this a stablizer bar or a sway bar? How unsafe is it to drive until I can get it repaired on Thursday?