"New York City," 1909 (but popularized by 1970s tourism promotion campaign), apparently from jazz musicians' use of apple for any city, especially a Northern one.

1936, from Gen. Emilio Mola's comment at the siege of Madrid during the Spanish Civil War that he would take the city with his four columns of troops outside it and his "fifth column" (quinta columna) in the city.

with year-dates, an occasional Roman method of identifying a given year by reference to the time passed since founding of the city, which in 1c. B.C.E. was calculated to have taken place in what we would call 753 B.C.E. Literally "from the city founded;" the elements are ab "from" (see ab-) + ablative of urbs "city" (see urban) + fem. past participle of condere "put together, store," from assimilated form of com- "together" (see com-) + -dere "put" (from PIE root *dhe- "to put, place").

city in Louisiana, U.S., a French translation of Choctaw (Muskogean) itti homma "red pole," perhaps in reference to a painted boundary marker.

emporium for stoner gear, by 1969 (noted in 1966 as the name of a specific shop in New York City selling psychedelic stuff), from head (n.) in the drug sense.

Jewish fraternal organization founded in New York City in 1843, Hebrew, literally "Sons of the Covenant," from bene, construct state of banim, plural of ben "son," + brith "covenant."

imaginary city built in air, 1830, translating Aristophanes' Nephelokokkygia in "The Birds" (414 B.C.E.). Cloud-land "place above the earth or away from the practical things of life, dreamland, the realm of fancy" is attested from 1840.

"U.S. financial world," 1836, from street in New York City that is home to many investment firms and stock traders, as well as NYSE. The street so called because it ran along the interior of the defensive wall of the old Dutch colonial town.

"the sea; naturally occurring salt water," late Old English sealtera watera. As an adjective from 1520s, "inhabiting salt water or the sea." Salt-water taffy attested by 1886; so called because it originally was sold at seashore resorts, especially Atlantic City, N.J. (see taffy).

"place where securities are bought and sold," 1809, from stock (n.2) + market. The original Stock Market (mid-14c.) was a fish and meat market in the City of London on or near the later site of Mansion House, so called perhaps because it occupied the site of a former stocks. Stock exchange is attested from 1773.