English

greenback

From green + back.

A compound of green + back

Proto-Indo-European *gʰreh₁- ‘to grow’

…

Proto-Germanic *grōniz

Proto-West Germanic *grōnī

Old English grēne

Middle English grene

English green

Proto-Germanic *baką ‘back’

Proto-West Germanic *bak

Old English bæc

Middle English bak ‘the back’

English back

Today it means

noun Any bill that is legal tender in the US (originally printed with green and black ink) issued by the Federal Reserve.

Language periods are conventional ranges, not dates for this word.

Etymograph / greenback