People sometimes use Big Brother to refer to a person, government, or organization when they think it has complete control over people and is always checking what they do.
[disapproval]
It's an attempt to control what reaches the public. Big Brother is watching.
Big Brother in British English
noun
1.
a person, organization, etc, that exercises total dictatorial control
2.
a television gameshow format in which a small number of people living in accommodation sealed off from the outside world are constantly monitored by TV cameras. Viewers vote each week to expel a person from the group until there is only one person left, who wins a cash prize
Word origin
C20: after a character in George Orwell's novel 1984 (1949)
big brother in American English
1.
one's older brother
2. US; [oftenB- B-]
a man who undertakes the role of friend and mentor to a disadvantaged boy, as through a social agency
3. [usuallyB- B-]
the state or some other organization regarded as ruthlessly invading the privacy of individuals in seeking to exercise control over them
Word origin
(sense 3) < concept in Orwell's novel 1984
Examples of 'Big Brother' in a sentence
Big Brother
You might want to have a talk with your big brother about that.
David and Leigh Eddings THE TREASURED ONE (2004)
The call eventually comes at about 6.00, during a trailer for a TV documentary about the Big Brother contestants and what they're doing now.
Scarlett Thomas GOING OUT (2002)
I went on some chat room for a while, then that Big Brother follow-up show was on and I've just been watching TV since then.