Big Brother is a fictional character and symbol in George Orwell's novel Nineteen Eighty-Four.
Nineteen Eighty-Four, often published as 1984, is a dystopian novel by English author George Orwell published in 1949.
Eric Arthur Blair, who used the pen name George Orwell, was an English novelist, essayist, journalist and critic.
He is ostensibly the leader of Oceania, a totalitarian state wherein the ruling Party wields total power "for its own sake" over the inhabitants.
In the society that Orwell describes, every citizen is under constant surveillance by the authorities, mainly by telescreens.
Surveillance is the monitoring of the behavior, activities, or other changing information, usually of people for the purpose of influencing, managing, directing, or protecting them.
Telescreens are fictional devices which operate as both televisions and security cameras.
The people are constantly reminded of this by the slogan "Big Brother is watching you": a maxim which is ubiquitously on display.
In modern culture the term "Big Brother" has entered the lexicon as a synonym for abuse of government power, particularly in respect to civil liberties, often specifically related to mass surveillance.
Civil liberties or personal freedoms are personal guarantees and freedoms that the government cannot abridge, either by law or by judicial interpretation, without due process.
Mass surveillance is the intricate surveillance of an entire or a substantial fraction of a population in order to monitor that group of citizens.
A lexicon is the vocabulary of a person, language, or branch of knowledge.