The idiom “break the bank” usually means spending so much money that it exhausts one’s funds or budget. It’s often used in a lighthearted or exaggerated way. For example, if someone says, “This new phone didn’t break the bank,” they’re saying it wasn’t too expensive.

Interestingly, the phrase originally came from gambling: in games like roulette, the “bank” refers to the house’s supply of money. If a player won more than the house could pay, they literally “broke the bank.”