A bank is a person who carries on the business of banking. The legal definition of the business of banking is:

conducting current accounts for customers
paying to the customer's order (e.g. the customer's cheques drawn on the bank), and
collecting the cheques deposited to the customers's account, as the customer's agent and crediting the proceeds to the customer's current account.

Police are agents or agencies empowered to enforce the law and to effect public and social order through the legitimate use of force. The term is most commonly associated with police departments of a state that are authorized to exercise the police power of that state within a defined legal or territorial area of responsibility. The word comes via French from the Latin politia (“civil administration”), which itself derives from the Ancient Greek π?λις, for polis ("city").[1]