*euthanasia*

pos>n. [ NL., fr. Gr. &unr_;; e'y^ well + &unr_; death, &unr_;, &unr_;, to die: cf. F. euthanasie. ] 1. An easy death; a mode of dying to be desired. “An euthanasia of all thought.” Hazlitt. [ 1913 Webster ]

The kindest wish of my friends is euthanasia. Arbuthnot.

2. the act or process of putting to death for humane purposes; -- used to refer to the killing of animals in order to relieve or avoid pain. [ PJC ]