Domain
late Middle English (denoting heritable or landed property): from French domaine, alteration (by association with Latin dominus ‘lord’) of Old French demeine ‘belonging to a lord’ (see demesne).
wiktionary
From Middle English demayne, demain(“rule”), from Old French demeine, demaine, demeigne, domaine(“power”), (French domaine), from Latin dominium(“property, right of ownership”), from dominus(“master, proprietor, owner”). See dame, and compare demain, danger, dungeon. Doublet of demesne.
etymonline
domain (n.)
c. 1600, "territory over which dominion is exerted," from French domaine "domain, estate," from Medieval Latin domanium "domain, estate," from Latin dominium "property, dominion," from dominus "lord, master, owner," from domus "house" (from PIE root *dem- "house, household"). A later borrowing from French of the word which became demesne.
Sense of "dominion, province of action" is from 1727. Meaning "range or limits of any department of knowledge or sphere of action" is from 1764. Internet domain name is attested by 1985. Via the notion of "ownership of land" comes legal eminent domain "ultimate or supreme lordship over all property in the state" is attested from 1738.
