In financial transactions, what does the term "green backs" refer to?

The term "greenbacks" refers specifically to US paper currency, most notably the dollar bills. The nickname originated from the green ink used on the back of the notes since they were first issued during the Civil War. This informal term emphasizes the physical representation of money in the form of cash that is widely used for transactions. It captures the essence of currency that is tangible and can be exchanged for goods and services, distinguishing it from digital or virtual forms of money. Greenbacks are associated with the historical context of American finance and the government’s backing of its currency, reinforcing its value in the economy.