"Mainstream" is, generally, the common current of thought of the majority. It is a term most often applied in the arts (i.e., music, literature, and performance). This includes:
* something that is ordinary or usual;
* something that is familiar to the masses;
* something that is available to the general public.
As such, the mainstream includes all popular culture, typically disseminated by mass media. The opposite of the mainstream are subcultures, countercultures, cult followings and underground cultures.
Additionally, "Mainstream" is sometimes a ''codeword'' used for one's own actual ethnocentric or subculture point of view, especially when delivered in a culture war speech.
Religiously, the mainstream specifically includes those in the "majority opinion" of theology specific to one's faith or denomination. For example: Those within Christianity who believe "Jesus Christ (to be) the literal Son of God and co-equally divine with God" would be viewed as the mainstream or majority opinion within Christendom; while those who held that the Messiah was a human prophet sent of God would be viewed as a minority, sectarian, or even heretical.