1683, a name applied disparagingly by Dutch settlers in New Amsterdam (New York) to English colonists in neighboring Connecticut. It may be from Dutch Janke, literally "Little John," diminutive of common personal name Jan; or it may be from Jan Kes familiar form of "John Cornelius," or perhaps an alteration of Jan Kees, dialectal variant of Jan Kaas, literally "John Cheese," the generic nickname the Flemings used for Dutchmen.

[I]t is to be noted that it is common to name a droll fellow, regarded as typical of his country, after some favorite article of food, as E[nglish] Jack-pudding, G[erman] Hanswurst ("Jack Sausage"), F[rench] Jean Farine ("Jack Flour"). [Century Dictionary, 1902, entry for "macaroni"]

Originally it seems to have been applied insultingly to the Dutch, especially freebooters, before they turned around and slapped it on the English. A less-likely theory (attested by 1832) is that it represents some southern New England Algonquian language mangling of English. In English a term of contempt (1750s) before its use as a general term for "native of New England" (1765); during the American Revolution it became a disparaging British word for all American natives or inhabitants. Contrasted with southerner by 1828. Shortened form Yank in reference to "an American" first recorded 1778. Latin-American form Yanqui attested in English by 1914 (in Mexican Spanish by 1835).

The rule observed in this country is, that the man who receives that name [Yankee] must come from some part north of him who gives it. To compensate us for giving each other nicknames, John Bull "lumps us all together," and calls us all Yankees. ["Who is a Yankee?" Massachusetts Spy, June 6, 1827]

1660s, "arouse by knocking at the door," from knock (v.) + up (adv.). However it is little used in this sense in American English, where the phrase means "get a woman pregnant" (1813), possibly ultimately from knock in a sense "to copulate with" (1590s; compare slang knocking-shop "brothel," 1860).

Knocked up in the United States, amongst females, the phrase is equivalent to being enciente, so that Englishmen often unconsciously commit themselves when amongst our Yankee cousins. [John Camden Hotten, "The Slang Dictionary," London, 1860]

very tall urban building, 1888, in a Chicago context, from sky (n.) + agent noun of scrape (v.). Used earlier for "ornament atop a building" (1883), "very tall man" (1857), "high-flying bird" (1840), "light sail at the top of a mast" (1794), and the name of a racehorse (1789). Compare cognate French gratte-ciel, from gratter "to scrape" + ciel "sky;" German Wolkenkratzer, from Wolke "cloud" + Kratzer "scraper."

cloud-cleaver, an imaginary sail jokingly assumed to be carried by Yankee ships. [W. Clark Russell, "Sailors' Word Book," 1883]

late 14c., nocioun, "a general concept, conception," from Latin notionem (nominative notio) "concept, conception, idea, notice," noun of action from past participle stem of noscere "come to know," from PIE root *gno- "to know." Coined by Cicero as a loan-translation of Greek ennoia "act of thinking, notion, conception," or prolepsis "previous notion, previous conception."

Meaning "an opinion, a view, a somewhat vague belief" is from c. 1600; that of "a not very rational inclination, a whim" is by 1746. Notions in the concrete sense of "miscellaneous small articles of convenience or utensils" (such as sold by Yankee peddlers) is by 1803, American English, via the idea of "clever product of invention."

"small-scale, petty" 1853, American English, colloquial, in reference to towns; see one + horse (n.). Probably from earlier use in reference to a carriage, sleigh, plow, etc., "drawn by a single horse" (1750); also "possessing only one horse" (of a farmer); hence "petty, on a small scale, of limited capacity or resources; inferior."

Shortly afterwards I took a stroll over the town. It was what is generally denominated a "one horse town," and I would think a pretty small pony at that. Two stores, one grocery, a stable, and four dwellings made up the sum of its buildings. ["Daguerreotyping in the Back Woods," in Yankee Notions, March, 1855]

"the southern United States," 1859, of obscure origin, first attested in the song of that name, which was popularized, if not written, by Ohio-born U.S. minstrel musician and songwriter Dan Emmett (1815-1904); perhaps a reference to the Mason-Dixon Line, but there are other well-publicized theories dating to the Civil War. Popularized nationwide in minstrel shows. Dixieland style of jazz developed in New Orleans c. 1910, so called by 1919 (in the name of a band).

It is interesting to remember that the song which is essentially Southern — "Dixie" — and that which is essentially Northern — "Yankee Doodle" — never really had any serious words to them. [The Bookman, June 1910]