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To rely on a future occurrence (even though it might not happen). I've really been banking on a holiday bonus this year—I don't have enough money to buy presents without it. I don't think you can bank on Tom coming tonight—he's really unreliable.
bank on something
Fig. to be so sure of something that one can trust it as one might trust a bank with one's money. I will be there on time. You can bank on it. I need a promise of your help. I hope I can bank on it.
Rely on, count on. For example, You can bank on Molly's caterer to do a good job. This expression alludes to bank as a reliable storage place for money. [Late 1800s]
To rely on someone or something: You can bank on her to get the job done when it has to be done quickly. I wouldn't bank on the bus arriving on time.