A currency is a standardization of money in any form, in use or circulation as a medium of exchange, for example banknotes and coins. A more general definition is that a currency is a system of money in common use within a specific environment over time, especially for people in a nation state. Under this definition, the British Pound sterling (£), euros (€), Japanese yen (¥), and U.S. dollars (US$) are examples of (government-issued) fiat currencies. Currencies may act as stores of value and be traded between nations in foreign exchange markets, which determine the relative values of the different currencies. Currencies in this sense are either chosen by users or decreed by governments, and each type has limited boundaries of acceptance; i.e., legal tender laws may require a particular unit of account for payments to government agencies.

मुद्रा पैसे या धन के उस रूप को कहते हैं जिस से दैनिक जीवन में क्रय और विक्रय होती है। इसमें सिक्के और काग़ज़ के नोट दोनों आते हैं। आमतौर से किसी देश में प्रयोग की जाने वाली मुद्रा उस देश की सरकारी व्यवस्था द्वारा बनाई जाती है। मसलन भारत में रुपया व पैसा मुद्रा है।