What is Change?

Legal Definition
The exchange of money for money. The giving, for example, dollars for eagles, dimes for dollars, cents for dimes. This is a contract which always takes place in the same place. By change is also understood small money. Poth. Contr. de Change, n. 1.
-- Bouviers Law Dictionary
Legal Definition
1. An alteration; substitution of one thing for another. This word does not connote either improvement or deterioration as a result. In this respect it differs from amendment, which, in law, always imports a change for the better.

2. Exchange of money against money of a different denomination. Also small coin. Also an abbreviation of exchange. See Change of venue.
-- Black's Law Dictionary