User blog comment:Blood Ox/Things To Do/@comment-6716431-20161018001819/@comment-16533050-20161018062432

It probably isn't clearly defined, as the devs/writers weren't really thinking "Franchise" when they made the game.

I always took the term Coin to mean a substitute for the name of the currency.

"It'll be 300 Coin, sir."

Whereas the term coins meant the actually physical objects.

"He found coins of various values at the bottom of the drawer."

Used together they should probably be something like this:

"He handed her two gold coins, worth 10 each, for a total of 20 Coin."