The word \'bank\' is derived from the Italian word \'banca\', which is derived from the German word for \'bench\'. Moneylenders in Northern Italy originally did business in open areas or open rooms where each lender worked from his own bench or table. The very first banks were probably in religious temples of the ancient world. Greek temples as well as private and civic entities conducted financial transactions such as loans, deposits, currency exchange, and the validation of coinage. Charging interest on loans and paying interest on deposits developed in ancient Rome.

A bank is a financial institution that provides banking services such as accepting deposits and making loans. There are also financial institutions that provide certain banking services without meeting the legal definition of a bank that are called non-banks.

The main functions of a bank include raising funds by attracting deposits, borrowing money in the inter-bank market, and issuing financial instruments in the money market or a securities market and then lending out most of these funds to borrowers including companies, individuals or government. Other services rendered by banks are facilitating international payments, issuing credit cards, provisioning safe locker facilities for valuables, project financing, merchant banking facility, online banking, personal banking, and investment banking. Typically, a bank generates profits from transaction fees on financial services and the interest charges on its loans.

There are several different types of banks including central banks, investment banks, merchant banks, private banks, savings banks, offshore banks, commercial banks, retail banks, and universal banks.

Present day banks need highly qualified, dedicated, and reliable staff because of intense competition from other financial institutions like insurance companies that provide some banking services to the public.