Currency

A Canadian One Dollar coin (more commonly referred to as a "Loonie"), a prime example of Modern currency

Currency (also known as money) refers to a standardized medium of exchange for trade. Currency evolved along with civilization, starting from simple barter and later using certain objects more often for trade, such as bolts of cloth or foodstuffs. In Eurasia, this eventually settled around masses of certain rare metallic elements such as gold and silver by the Iron Age for reasons of convenience and the jewelry trade, which was helped considerably by the introduction of standardized systems of weights and measures. The degree to which currency was used greatly increased with urbanization, as people became more interdependent, which lead to the rise of systems to manage finance, lending of currency at interest, and paper currency for sake convienence (starting in China). In the modern world, most currencies are backed by the legal authority of the issuing government on the matter of transactions, with computer technology being increasingly used to make things more efficient.

Currency usually concentrates in the possession of a fairly small percentage of the population of a society, giving said demographic considerable power and influence. If too much of the available currency moves into the hands of of too small a section of the population, social issues inevitably result.

Currency in Science Fiction and Fantasy

• In the Star Trek, the United Federation of Planets has abolished currency, although other governments such as the Klingon Empire still issue currencies. An analog to the Gold Standard is used by the Ferengi -- and honored by others powers -- based around "gold-pressed latinum." Due to energy shortages on-board the USS Voyager, a system of exchange referred to as "replicator rations" is created to manage the use of the ship's strained resources.
• In Star Wars, the standard unit of currency is the "credit". The earliest mention of credits was Qui-Gon Jinn's failed attempt to purchase a hyperdrive with "Republic Daktaris"; these "Republic credits" were not valued on Tatooine at the time. Presumably these credits are issued and backed by the Galactic Republic and, later, the Galactic Empire.
• In Stargate, Naquadah is often used as currency.
• In the Terry Pratchett Discworld novel Making Money, the plot focuses around the nature of money and the introduction of banknotes to replace a gold based system of currency, which is the norm for most fantasy universes.