A oil light indicator came on the dashboard. What does this mean?

It means low oil pressure. Engine bearings run on a thin film of pressurized oil. The oil pump moves a volume of oil and if the bearings are tight enough, the pressure remains at a normal level with the pressure regulator limiting the maximum pressure.

If the pressure has dropped, it's usually an indication of bearing wear. Of course it CAN mean that you're out of oil, because if there isn't any oil to pump, the engine can't build oil pressure; but hopefully you know better than that.

Low oil pressure is almost always an indication of worn bearings. In some rare circumstances it can also be caused by a worn or damaged oil pump.