> Currencies are systems of value exchange.
No. That's money. Not all currencies are money. Zimbabwean dollars, for example, are a currency but they are not money. "Worthless currency" is not an oxymoron, but "worthless money" is. Money has value by definition. Currency doesn't.
> It is the reason why the term is derived from the word "current"
The etymology of a word has very little to do with its current meaning. "Calculate" is derived from the latin word for "stone", but that doesn't mean that calculating has anything to do with stones. (It did at one time, but not any more.)
> Currency is an algebra of the domain of money measured over the economy of that money's exchanges including the changes in inflation in relation to the money value of a dollar in relation to bread.
That might be a useful definition, but it's not the one used by economists. "Currency" is a proper subset of "money", which also comprises bank money [1], cash-equivalent securities [2] and commodities [3], all of which are money and none of which are currencies.
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[1] https://www.merriam-webster.com/dictionary/bank%20money
[2] https://www.investopedia.com/terms/c/cashequivalents.asp
[3] https://en.wikipedia.org/wiki/Commodity_money