demesne has several senses, mainly following from the legal one mentioned, but note that it is just another form of the word domain. (and is pronounced /di MANE/ or /di MENE/)

By her Fine foote, Straight leg, and Quiuering thigh, And the Demeanes, that there Adiacent lie. -WS, Romeo & Juliet

One wide expanse... That deep-browed Homer ruled as his demesne [rime serene]. -Keats