What does it mean when my brake light (on dashboard) is staying on in my 2000 dodge stratus?

That light is a combination warning light.
It usually comes on when you set your parking brake, so check that your parking brake is off.

It also comes on when your brake system has a problem. it means that one of your two brake systems has problems. Check your brake fluid reservoir, and see if either one is low on fluid. If so, then check the back side of the affected tires and look for brake fluid leakage., and if the fluid is low, get your vehicle checked out as soon as possible