S: (n) currency (the metal or paper medium of exchange that is presently used)
S: (n) medium of exchange, monetary system (anything that is generally accepted as a standard of value and a measure of wealth in a particular country or region)
S: (n) standard, criterion, measure, touchstone (a basis for comparison; a reference point against which other things can be evaluated) "the schools comply with federal standards"; "they set the measure for all subsequent work"
S: (n) system of measurement, metric (a system of related measures that facilitates the quantification of some particular characteristic)