anesthesia

1. Total or partial loss of sensation, especially tactile sensibility, induced by disease, injury, acupuncture, or an anesthetic, such as chloroform or nitrous oxide.

2. Local or general insensibility to pain with or without the loss of consciousness, induced by an anesthetic.

3. A drug, administered for medical or surgical purposes, that induces partial or total loss of sensation and may be topical, local, regional, or general, depending on the method of administration and area of the body affected.

Word History: The following passage, written on November 21, 1846, by Oliver Wendell Holmes, a physician-poet and the father of the Supreme Court justice of the same name, allows us to pinpoint the entry of anesthesia and anesthetic into English: "Every body wants to have a hand in a great discovery. All I will do is to give you a hint or two as to names—or the name—to be applied to the state produced and the agent. The state should, I think, be called 'Anaesthesia' [from the Greek word anaisthēsia, "lack of sensation"]. This signifies insensibility.... The adjective will be 'Anaesthetic.' Thus we might say the state of Anaesthesia, or the anaesthetic state." This citation is taken from a letter to William Thomas Green Morton, who in October of that year had successfully demonstrated the use of ether at Massachusetts General Hospital in Boston. Although anaesthesia is recorded in Nathan Bailey's Universal Etymological English Dictionary in 1721, it is clear that Holmes really was responsible for its entry into the language. The Oxford English Dictionary has several citations for anesthesia and anesthetic in 1847 and 1848, indicating that the words gained rapid acceptance.