Definition of "big brother" [big brother]

• An older brother. (noun)
• A man who assumes the role of an older brother, as by providing guidance or protection. (noun)
• An omnipresent, seemingly benevolent figure representing the oppressive control over individual lives exerted by an authoritarian government. (noun)
• A state, organization, or leader regarded in this manner. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "He was known as the lazy one, the careless boy who would always need a big brother to watch over him."
• "Six-year-old big brother Joshua and two-year-old sister Mckenna giggled with glee and excitement."
• "Not one, but two little Antonians to follow big brother Caesarion around the way my brothers followed me."