domain (n.)

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.

"in the year of the Christian era," 1570s, Latin, literally "in the year of (our) Lord," from ablative of annus "year" (see annual (adj.)) + Late Latin Domini, genitive of Dominus "the Lord" (see domain). Also see A.D.

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."