What is an anti roll bar?
An anti roll bar is a strengthening beam that stiffens the ride and prevents sway. Makes the handling better.
A bar you put across the refrigerator so you can't get to the rolls.
It is part of the steering and suspensions system, that can also be known as a sway bar. This is located under your car and it connected by steering links to the steering knuckles. It prevents sway, with the car, and keeps the car from swaying/rolling on turns. It also makes both sides of the steering system preform equally.