greenback
noun
1
a one-dollar note US, 1862.
2
a one-pound note. A green-coloured banknote, first issued in 1917, the colour remained despite diminishing size and value, except for the period 1940–48 when it was blue, until 1988 when it ceased to be legal tender. Sometimes shortened to 'greenie' UK, 1961.
3
an Australian one-pound note. Fell out of use after the introduction of decimal currency in 1966 AUSTRALIA, 1919.
4
in surfing, a swell that has not broken US, 1963.
5
an implement for re-railing a train carriage or engine US, 1946