Why Do We Call Coins "Change"?

By GovMint :

We call coins "change" because the term initially referred to the money that was returned to someone after they had paid for something with more than the required amount. Over time, the word "change" has evolved to refer to circulating coins with tiny denominations, as these are often the coins given back in such transactions. Getting your "change" meant receiving the difference back in coin form, hence the association.

Sources Used:

https://www.merriam-webster.com/dictionary/change