A "Brain Sister" is a girl who wears glasses and finished high school. However, there is some debate as to whether or not a "Brain Sister" actually wears glasses.
"She was only twentyseventeen, she was a lonely beauty queen, she was a brain sister, Texas Instruments all day..."
Quoted from the Limozeen song "Brain Sister"
Quoted from the Limozeen song "Brain Sister"
by Garboth March 19, 2008
Get the Brain Sistermug. An attractive twenty-something year old who is constantly occupied with a Texas Instruments calculator.
by Daniel C. Johnston July 31, 2006
Get the brain sistermug.