landlord (n.)

Old English lond, land, "ground, soil," also "definite portion of the earth's surface, home region of a person or a people, territory marked by political boundaries," from Proto-Germanic *landja- (source also of Old Norse, Old Frisian Dutch, Gothic land, German Land), perhaps from PIE *lendh- (2) "land, open land, heath" (source also of Old Irish land, Middle Welsh llan "an open space," Welsh llan "enclosure, church," Breton lann "heath," source of French lande; Old Church Slavonic ledina "waste land, heath," Czech lada "fallow land"). But Boutkan finds no IE etymology and suspects a substratum word in Germanic,

Etymological evidence and Gothic use indicates the original Germanic sense was "a definite portion of the earth's surface owned by an individual or home of a nation." The meaning was early extended to "solid surface of the earth," a sense which once had belonged to the ancestor of Modern English earth (n.). Original senses of land in English now tend to go with country. To take the lay of the land is a nautical expression. In the American English exclamation land's sakes (1846) land is a euphemism for Lord.

mid-13c., laverd, loverd, from Old English hlaford "master of a household, ruler, feudal lord, superior; husband," also "God," translating Latin dominus, Greek kyrios in the New Testament, Hebrew yahweh in the Old (though Old English dryhten was more frequent). Old English hlaford is a contraction of earlier hlafweard, literally "one who guards the loaves," from hlaf "bread, loaf" (see loaf (n.)) + weard "keeper, guardian" (from PIE root *wer- (3) "perceive, watch out for").

Compare lady (literally "bread-kneader"), and Old English hlafæta "household servant," literally "loaf-eater." For the contraction, compare Harold. The modern monosyllabic form emerged 14c. Meaning "an owner of land, houses, etc.," is from c. 1300; the sense in landlord. As the "usual polite or respectful form of address to a nobleman under the rank of a duke, and to a bishop" [OED] from 1540s. As an interjection from late 14c. Lords "peers of England," especially as represented in parliaments, is from mid-15c.

Lord's Prayer is from 1540s. Year of our Lord is from late 14c. (translating Latin anno domini) in reference to the incarnation of God in Christ. Lord knows (who, what, why, etc.), expressing a state of ignorance, is from 1711. Lord of the Flies (1907) translates Beelzebub (q.v.); William Golding's book was published in 1954. To drink like a lord is from 1620s.

also slum-lord, 1899, from slum landlord (1885); see slum (n.) + landlord.