to spend more money on something than you normally would. usually entails tapping into reserve funds (line of credit, mortgage etc.)
"We decided to break the bank this winter and take a 6 week vacation to Australia and the South Pacific."
by Bungalow Bill January 24, 2007
To make a shitload of money.
When Joe deposited 700 G's into his savings account at once, the bank broke.
by Nick D January 12, 2004