Learned something from the AM radio this morning while on the way to work. A certain Mr. Lim was being interviewed and as additional information for the public and for media, he stated the difference between the terms brownout and blackout. He also said that to refer to the correct thing, we all should use the term blackout.
On the other hand, blackout is the term that we should use nowadays, because the power providers don't lower the voltage anymore, they immediately turn off the power distribution in one locality when there isn't enough to go around. So you either have electricity or not. Hence, blackout.