A bank is an institution that provides financial service, particularly taking deposits and extending credit.
Currently the term bank is generally understood as an institution that holds a banking license. Banking licenses are granted by bank regulatory authorities and provide rights to conduct the most fundamental 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, a so called non-banking financial company.
Banks have a long history, and have influenced economies and politics for centuries.
The word bank is derived from the Italian banca, which is derived from German language and means bench. The terms bankrupt and "broke" are similarly derived from banca rotta, which refers to an out of business bank, having its bench physically broken. Money lenders in Northern Italy originally did business in open areas, or big open rooms, with each lender working from his own bench or table.
Typically, a bank generates profits from transaction fees on financial services and on the interest it charges for lending.