In the show, contestants called "housemates" (or "House Guests") live together in a specially-constructed house that is isolated from the outside world.
Big Brother contestants are isolated in the house, without access to television, radio or the Internet.
They are not permitted routine communication with the outside world.
Most versions of Big Brother follow the weekly eviction format, broadcast over approximately three months for 16 contestants.
The contestants are required to do housework and are assigned tasks by the producers of the show (who communicate with the housemates via the omnipresent authority figure known to them only as "Big Brother").
In the earlier series of Big Brother, there were 10 contestants with evictions every two weeks.
However, the UK version introduced a larger number of contestants with weekly evictions.
The housemates with the most nominations are then announced, and viewers are given the opportunity to vote via telephone for the nominee they wish to be evicted or saved for eviction. Some more recent editions have since included additional methods of voting, such as voting through social media and smartphone applications.
Occasionally, non-standard votes occur, where two houseguests are evicted at once or no one is voted out.
During their stay in the house, contestants are continuously monitored by live television cameras as well as personal audio microphones.
English-language editions of the program are often referred to as "BB".
In 2001, the US version adopted a different format during its second season, where the contestants are encouraged to strategize to advance in the game; in this format the contestants themselves vote to evict each other.