Mainstream media is the term often used to describe the collective group of big TV, radio and newspapers in the United States. Mainstream implies that the news being produced is for the benefit and enlightenment of the mainstream population—the majority of people living in the US. Mainstream media include a number of communication mediums that carry almost all the news and information on world affairs that most Americans receive. The word media is plural, implying a diversity of news sources.
However, mainstream media no longer produce news for the mainstream population—nor should we consider the media as plural. Instead it is more accurate to speak of big media in the US today as the corporate media and to use the term in the singular tense—as it refers to the singular monolithic top-down power structure of self-interested news giants.