The Oxford English Dictionary Online (2nd edition, 1989; online version Sep. 2011) provides the following definitions of euthanasia:
"A gentle and easy death... [T]he means of bringing about a gentle and easy death...
In recent use: The action of inducing a gentle and easy death. Used esp. with reference to a proposal that the law should sanction the putting painlessly to death of those suffering from incurable and extremely painful diseases."
Michael Manning, MD, in his 1998 book Euthanasia and Physician-Assisted Suicide: Killing or Caring?, traced the history of the word euthanasia:
"The term euthanasia... originally meant only 'good death,' but in modern society it has come to mean a death free of any anxiety and pain, often brought about through the use of medication. Most recently, it has come to mean 'mercy killing' -- deliberately putting an end to someone's life in order to spare the individual's suffering."
BBC News stated in its July 1, 1999 special report titled "A Euthanasia Glossary":
"Euthanasia has many definitions. The Pro-Life Alliance defines it as: 'Any action or omission intended to end the life of a patient on the grounds that his or her life is not worth living.' The Voluntary Euthanasia Society looks to the word's Greek origins - 'eu' and 'thanatos,' which together mean 'a good death' - and say a modern definition is: 'A good death brought about by a doctor providing drugs or an injection to bring a peaceful end to the dying process.' Three classes of euthanasia can be identified -- passive euthanasia, physician-assisted suicide and active euthanasia -- although not all groups would acknowledge them as valid terms."
Ian Dowbiggin, PhD, Professor of History at the University of Prince Edward Island, wrote in his 2005 book A Concise History of Euthanasia: Life, Death, God, and Medicine:
"The influential scientist and philosopher Francis Bacon (1561-1626)... was the first in history since Roman historian Suetonius (c. 70-140 AD)... to use the term 'euthanasia'... [B]oth Bacon and Suetonius employed the word in its etymological meaning, that is, to signify an easy death through the mitigation of pain rather than a death hastened by a physician through the administration of poison."
Jonathan Moreno, PhD, wrote in his 1995 book Arguing Euthanasia: The Controversy Over Mercy Killing, Assisted Suicide, and the "Right to Die":
"Strictly speaking, the term 'euthanasia' refers to actions or omissions that result in the death of a person who is already gravely ill. Techniques of active euthanasia range from gunfire to lethal injection, while passive euthanasia can be achieved by failing to treat a pneumonia or by witholding or withdrawing ventilatory support."