c. 1200, from Old French cite "town, city" (10c., Modern French cité), from earlier citet, from Latin civitatem (nominative civitas; in Late Latin sometimes citatem) originally "citizenship, condition or rights of a citizen, membership in the community," later "community of citizens, state, commonwealth" (used, for instance of the Gaulish tribes), from civis "townsman," from PIE root *kei- (1) "to lie," also forming words for "bed, couch," and with a secondary sense of "beloved, dear."
Now "a large and important town," but originally in early Middle English a walled town, a capital or cathedral town. Distinction from town is early 14c. OED calls it "Not a native designation, but app[arently] at first a somewhat grandiose title, used instead of the OE. burh"(see borough).
Between Latin and English the sense was transferred from the inhabitants to the place. The Latin word for "city" was urbs, but a resident was civis. Civitas seems to have replaced urbs as Rome (the ultimate urbs) lost its prestige. Loss of Latin -v- is regular in French in some situations (compare alleger from alleviare; neige from nivea; jeune from juvenis. A different sound evolution from the Latin word yielded Italian citta, Catalan ciutat, Spanish ciudad, Portuguese cidade.
London is the city from 1550s. As an adjective, "pertaining to a city, urban," from c. 1300. City hall "chief municipal offices" is first recorded 1670s; to fight city hall is 1913, American English. City slicker "a smart and plausible rogue, of a kind usu. found in cities" [OED] is first recorded 1916 (see slick (adj.)). City limits is from 1825.
The newspaper city-editor, who superintends the collection and publication of local news, is from 1834, American English; hence city desk attested from 1878. Inner city first attested 1968.
"fortress commanding a city," 1580s, from French citadelle (15c.), from Italian cittadella, diminutive of Old Italian cittade "city" (Modern Italian citta), from Latin civitatem (nominative civitas; also source of Portuguese citadella, Spanish ciuadela; see city).
1540s, "pertaining to a city or citizenship," originally in civic crown (Latin corona civica), a chaplet of oak leaves awarded to one who saved the life of a fellow citizen in battle, from Latin civicus "of a citizen," adjectival derivative of civis "townsman" (see city). Sense of "having to do with citizens" is from 1790.
c. 1600, "to bring out of barbarism, introduce order and civil organization among, refine and enlighten," from French civiliser, verb from Old French civil (adj.), from Latin civilis "relating to a citizen, relating to public life, befitting a citizen; popular, affable, courteous," alternative adjectival derivative of civis "townsman" (see city). Intransitive meaning "become civilized" is from 1868. Related: Civilized; civilizing.
late 14c., "judge or authority on civil law," from noun use of Old French civilien "of the civil law," created from Latin civilis "relating to a citizen, relating to public life, befitting a citizen; popular, affable, courteous," alternative adjectival derivative of civis "townsman" (see city). Sense of "non-military and non-clerical person, one whose pursuits are those of civilian life" is attested by 1766. As an adjective, "pertaining to or characteristic of a civilian," from 1640s.