* Consult your owner's manual: This is the most reliable source. The manual will have a diagram of the dashboard lights and explain what each one signifies.
* Look closely at the light: Many lights have small symbols next to them (like a tire, an engine, etc.) that give a clue to their meaning.
* Describe the light: If you can describe the symbol (or lack thereof) next to the light, or the light's shape, I might be able to give you a more educated guess. For example, is it a steady light, flashing light, or does it illuminate only under certain conditions?
Without more information, it's impossible to say definitively what the orange light means.