What is an international monetary system? What is the difference between spot and forward exchange rates?

What is an international monetary system?
What is the difference between spot and forward exchange rates?
What is the difference between floating- and fixed-exchange rates?
Differentiate between devaluation/revaluation of a currency and
depreciation/appreciation of a currency.
What is meant by a soft or weak currency? A hard or strong currency?
What are the two broad categories of the various currency regimes?
What are the subgroups of these two broad categories?