Each of these terms can correctly be used to refer to a place where something is deposited for safekeeping. A safe deposit box stored in a bank vault is a depository or depositary. The latter word, however, is more often used to refer not to a place for safekeeping but to a group or even an individual entrusted with the preservation of something. The officers of a bank or the trustees of a museum, for instance, would more likely be called depositaries than depositories.
Dictionary of problem words and expressions. Harry Shaw. 1975.