Definition of goldback:
(n) :
(US, slang, historical) A kind of gold certificate with an orange back.
(n) :
Any member of species Pentagramma triangularis of ferns.
(n) :
Any member of genus Pityrogramma of ferns.
(n) :
A fractional gold commercial product marketed as a local currency and commodity which has seen limited use in some U.S. states, shaped like a banknote but containing a small amount of 24-karat gold.