Why isn't "demesne" pronounced the way it's spelled? Our word actually began as "demayn" or "demeyn" in the 14th century, when it was borrowed from Anglo-French property law. At that time, the Anglo-French form was "demeine." Later, the Anglo-French spelling changed to "demesne," perhaps by association with another term from Anglo-French property law: mesne, meaning "intermediate." ("Mesne" has entered English as a legal term as well.) According to rules of French pronunciation, the "s" was silent and the vowel was long. English speakers eventually followed suit, adopting the "demesne" spelling. Our word domain (which overlaps with the meaning of "demesne" in some applications) also comes from Anglo-French demeine.
the vast and frozen demesne of the northern tundra the view that the issue is not in the demesne of the courts and is something that should be decided by the state legislature
Recent Examples on the WebNow, 15 seasons later, Whittingham has beamed himself to a different sphere, a rare demesne of security, a comfort zone as wide as Jimmy Kimmel’s, hovering consistently in a most lofty realm. Gordon Monson, The Salt Lake Tribune, 12 Nov. 2021 In Loki, the titular character finds himself in the bizarre (almost Brazil style) demesne of the Time Keepers, an organization devoted to ensuring the sanctity of the timeline. Erik Kain, Forbes, 5 Apr. 2021 Still, enough of the original grounds remain as part of Biltmore’s grandeur as to suggest, even today, a demesne with a castle at its center. Stuart Ferguson, WSJ, 29 Sep. 2017
Word History
Etymology
Middle English, from Anglo-French demesne, demeine — more at domain