demesne

From Middle English demayne, from Anglo-Norman demeyne, demene et al., Old French demeine, demaine, demeigne, domaine (“power”) (whence French domaine (“domain”)), a noun use of an adjective, from Latin dominicus (“belonging to a lord or master”), from dominus (“master, proprietor, owner”). See dame. Doublet of domain. The spelling with non-etymological s is partly due to influence from mesne and partly for the purpose of indicating a long vowel, as the s quiesced before a consonant; compare aisle, isle, Carlisle.