Black Mail
The Cyclopedic Law Dictionary · Walter A. Shumaker and George Foster Longsdorf; ed. James C. Cahill · 1922
The Cyclopedic Law Dictionary
Rents reserved, payable in work, grain, and the like. Such rents were called "black mail" (reditus nigri), in distinction from white rents (blanche firmes), which were rents paid in silver. A yearly payment made for security and land about the middle of the sixteenth century, and laid the inhabitants under contribution. Hume, Hist. Eng. vol.
1, p. 473; Id. vol. 2, App. No. 8; Cowell.
In common usage the term signifies the obtaining of money by a demand accompanied by threats of prosecution, exposure or injury in case of nonpayment. The corrupt taking under color of office is "extortion." (q. V.)