D defs.my
Entry 1 sense Webster, 1913

Greenback

/grēn'-băkˌ/ · Green·back · IPA /ɡrˈiːnbˌæk/
01 n. One of the legal tender notes of the United States; a note of paper currency of the United States; -- first issued in 1862, and having the …
  1. 1.
    One of the legal tender notes of the United States; a note of paper currency of the United States; -- first issued in 1862, and having the devices on the back printed with green ink, to prevent alterations and counterfeits.