Greenback

Greenback was officially the United States note, first issued by the U.S. Treasury in 1862 as legal tender fiduciary paper money to help finance the Civil War. Their value in gold at one time (1864) was below 40 cents. In 1879, they became redeemable in gold. However, when the United States went off the gold standard in 1933, the greenbacks again became irredeemable. The highest amount outstanding was $450,000,000.