Black Mirror creator, Charlie Brooker, explained that he chose this name because when viewers watch something on TV or computer, they see their own reflection when the screen goes black for a couple of seconds, as if it's an actual black mirror.
The creator said the concept of looking at yourself in a black mirror is 'cold and horrifying', which also applies to the series itself. The title reflects the show's atmosphere.
The creator says Black Mirror is the perfect title for the show. For example, he couldn't use 'Spooky Technology Time' because it's 'rubbish'. No other title could match the content of the series as well as Black Mirror.
The creator intended for the show to be called Black Mirror because he found it fascinating how at the end of every episode, the viewers see themselves in the black screen and reflect on the show's events.
Fans believe the content of the show is representative of modern day society and its morbidness. Thus, they believe Black Mirror is meant to reflect the ugly nature of society as a whole.
According to the creator, there's a 'cold, shiny screen' on every electronic device we use such as smartphones, tablets and TVs. The black mirror refers to these gadgets and how people are addicted to them.
The title is meant to make people think about the dangers and negative effects of technology which is shown in the episodes.
Since the title does not directly reflect the content of the show, it keeps viewers engaged to find out the meaning of the title and makes them think of possible explanations for the title on their own.