In economics, cash is money in the physical form of currency, such as banknotes and coins. In bookkeeping and financial accounting, cash is current assets comprising currency or currency equivalents that can be accessed immediately or near-immediately (as in the case of money market accounts). Cash is seen either as a reserve for payments, in case of a structural or incidental negative cash flow or as a way to avoid a downturn on financial markets. Etymology. The English word cash originally meant 'money box', and later came to have a secondary meaning 'money'.
https://en.wikipedia.org/wiki/Cash