c. 1300, demeine, demeyne (modern spelling by late 15c.), "power; dominion; control, possession," senses now obsolete, from Anglo-French demesne, demeine, Old French demaine "land held for a lord's own use," from Latin dominicus "belonging to a master," from dominus "lord, master," from domus "house" (from PIE root *dem- "house, household").
Re-spelled by Anglo-French legal scribes under influence of Old French mesnie "household" (and the concept of a demesne as "land attached to a mansion") and their fondness for inserting -s- before -n-. Essentially the same word as domain.
Meaning "a manor house and near or adjacent land," kept and occupied by the lord and his family, is from late 14c., hence "any landed estate" (late 14c.). Related: Demesnial.
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.
Proto-Indo-European root meaning "house, household." It represents the usual Indo-European word for "house" (Italian, Spanish casa are from Latin casa "cottage, hut;" Germanic *hus is of obscure origin).
It forms all or part of: Anno Domini; belladonna; condominium; dame; damsel; dan "title of address to members of religious orders;" danger; dangerous; demesne; despot; Dom Perignon; domain; dome; domestic; domesticate; domicile; dominate; domination; dominion; domino; don (n.) "Spanish, Italian, and Portuguese title of respect;" Donna; dungeon; ma'am; madam; madame; mademoiselle; madonna; major-domo; predominant; predominate; timber; toft.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit damah "house;" Avestan demana- "house;" Greek domos "house," despotēs "master, lord;" Latin domus "house," dominus "master of a household;" Armenian tanu-ter "house-lord;" Old Church Slavonic domu, Russian dom "house;" Lithuanian dimstis "enclosed court, property;" Old Norse topt "homestead."
c. 1300, maner, "mansion, habitation, country residence, principal house of an estate," also "a manorial estate," from Anglo-French maner, Old French manoir "abode, home, dwelling place; manor" (12c.), noun use of maneir "to dwell," from Latin manere "to stay, abide," from PIE root *men- (3) "to remain." As a unit of territorial division in Britain and some American colonies (usually "land held in demesne by a lord, with tenants") it is attested from 1530s.
c. 1300, "young man;" also "youthful knight, novice in arms," from Old French bacheler, bachelor, bachelier (11c.) "knight bachelor," a young squire in training for knighthood, also "young man; unmarried man," and a university title. A word of uncertain origin.
Perhaps it is from Medieval Latin baccalarius "vassal farmer, adult serf without a landholding," one who helps or tends a baccalaria "field or land in the lord's demesne" (according to old French sources, perhaps from an alteration of vacca "a cow" and originally "grazing land" [Kitchin]).
But Wedgwood points out that the baccalarii "were reckoned as rustici, and were bound to certain duty work for their lord. There is no appearance in the passages cited of their having had any military character whatever." (He favored a Celtic origin). Or perhaps it is from Latin baculum "a stick," because the squire would practice with a staff, not a sword. "Perhaps several independent words have become confused in form" [Century Dictionary].
The meaning in English expanded by early 14c. to "young unmarried man" and by late 14c. to "one who has taken the lowest degree in a university." Bachelor party as a pre-wedding ritual is by 1882.