The quality of being exchangeable (especially the ability to convert a currency into gold or other currencies without restriction).

Roget 13: identity, sameness; coincidence, coalescence; convertibility; equality etc. 27; selfness^†, self, oneself; identification.    monotony, tautology etc. (repetition) 104.    facsimile etc. (copy) 21; homoousia: alter ego etc. (similar) 17; ipsissima verba [Lat.] etc. (exactness) 494; same; self, very, one and the same; very thing, actual thing; real McCoy; no other; one and only; in the flesh.    ... show more

Roget 144: conversion, reduction, transmutation, resolution, assimilation; evolution, sea change; change of state; assumption; naturalization; transportation; development [Biol.], developing.    [photography] [conversion of currency] conversion of currency, exchange of currency; exchange rate; bureau de change.    chemistry, alchemy; progress, growth, lapse, flux.    passage; transit, transition; transmigration, shifting etc. v.; phase; conjugation; convertibility.    crucible, alembic, caldron, retort.    convert, pervert, renegade, apostate.    ... show more

Dutch: inwisselbaarheid
Polish: wymienialność waluty