E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Greenbacks.
Bank notes issued by the Government of the United States in 1862, during the Civil War; so called because the back is printed in green. In March, 1878, the amount of green-backs for permanent circulation was fixed at 346,681,016 dollars; in rough numbers, about 70 millions sterling.
