Receiving money for the purpose of saving it for an indefinite period of time. A catchier derivative of money in the bank. Also pertains to the use of the word bank to mean money itself, rather than a place money. "Tank," in this case, refers to one's wallet, an actual bank, or any other place where money is kept. "Bank in the tank," like money in the bank, can also refer to reliability of an event. Often associated with ghetto terminology.