Function: noun
Date: 1844
1 : an older brother
2 : a man who serves as a companion, father figure, and role model for a boy
3 capitalized both Bs [ Big Brother, personification of the power of the state in 1984 (1949) by George Orwell] a : the leader of an authoritarian state or movement b : an all-powerful government or organization monitoring and directing people's actions <data banks that tell Big Brother all about us ― Herbert Brucker>