My very wise friend Ala saw my post on ribaa/oppressive economics in Quran and mentioned these two ayahss to me about currency:
Such (being their state), we raised them up (from sleep), that they might question each other. Said one of them, “How long have ye stayed (here)?” They said, “We have stayed (perhaps) a day, or part of a day.” (At length) they (all) said, “Allah (alone) knows best how long ye have stayed here…. Now send ye then one of you with this money of yours (bi wariqikum) to the town: let him find out which is the best food (to be had) and bring some to you, that (ye may) satisfy your hunger therewith: And let him behave with care and courtesy, and let him not inform any one about you (18/19)
Among the People of the Book are some who, if entrusted with a hoard of gold (bi qintaarin), will (readily) pay it back; others, who, if entrusted with a single silver coin, (bi dinaarin) will not repay it unless thou constantly stoodest demanding, because, they say, “there is no call on us (to keep faith) with these ignorant (Pagans).” but they tell a lie against Allah, and (well) they know it. (3/75)
So three words are used:
In time, we will see how these words may be analysed linguistically.