genetic disorder causing developmental and intellectual delays, 1961, from J.L.H. Down (1828-1896), English physician; chosen as a less racist name for the condition than earlier mongolism.
1867, American English, originally Kuklux Klan, a made-up name, supposedly from Greek kuklos, kyklos "circle" (see cycle (n.)) + English clan. Originally an organization of former Confederate officers and soldiers, it was put down by the U.S. military in the 1870s. Revived 1915 as a national racist Protestant fraternal organization, it grew to prominence but fractured in the 1930s. It had a smaller national revival 1950s as an anti-civil rights group, later with anti-government leanings. In late 19c. often simply Kuklux.
fem. proper name, Danish shortened form of Katherine. Rare before 1928; a top-10 name for girls born in the U.S. 1951-1968.
The modern pejorative use in reference to a person regarded as ignorant, meddlesome, entitled, racist, or generally negative, is attested by 2005, originally often with reference to meanness or stupidity, and exploded in popularity 2018, with more emphasis on the racism and privilege. Its use as rhetorical shorthand probably was encouraged, if not inspired by, the 2004 movie "Mean Girls" (screenplay by Tina Fey) and by U.S. comedian Dane Cook's 2005 stand-up act, both of which produced memes and Twitter references. Claims that it originated in African-American circles are unsupported.
Beth Harpaz's 2001 book "Girls in the Van," about Hillary Clinton's U.S. Senate campaign, reports that Clinton's assistants Karen Dunn and Karen Finney were known as The Karens. Finney went on to a career as a commentator, and some of the earliest abstract uses of Karen in the late 2000s are as the personification of a liberal do-gooder.
1507, "the western hemisphere, North and South America," in Cartographer Martin Waldseemüller's treatise "Cosmographiae Introductio," from Modern Latin Americanus, traditionally after Amerigo Vespucci (1454-1512) who made two trips to the New World as a navigator and claimed to have discovered it. His published works put forward the idea that it was a new continent, and he was first to call it Novus Mundus "New World." Amerigo is more easily Latinized than Vespucci (Latin Vesputius, which might have yielded place-name Vesputia). The sense in English naturally was restricted toward the British colonies, then the United States.
It is a thousand pities that the puny witticisms of a few professional objectors should have the power to prevent, even for a year, the adoption of a name for our country. At present we have, clearly, none. There should be no hesitation about "Appalachia." In the first place, it is distinctive. "America" is not, and can never be made so. We may legislate as much as we please, and assume for our country whatever name we think right — but to use it will be no name, to any purpose for which a name is needed, unless we can take it away from the regions which employ it at present. South America is "America," and will insist upon remaining so. [Edgar Allan Poe, "Marginalia," in Graham's Magazine, Philadelphia, December 1846]
FREDONIA, FREDONIAN, FREDE, FREDISH, &c. &c. These extraordinary words, which have been deservedly ridiculed here as well as in England, were proposed sometime ago, and countenanced by two or three individuals, as names for the territory and people of the United States. The general term American is now commonly understood (at least in all places where the English language is spoken,) to mean an inhabitant of the United States; and is so employed, except where unusual precision of language is required. [John Pickering, "A Vocabulary, or Collection of Words and Phrases Which Have Been Supposed to be Peculiar to the United States of America," Boston, 1816]
The man's name Amerigo is Germanic, said to derive from Gothic Amalrich, literally "work-ruler." The Old English form of the name has come down as surnames Emmerich, Emery, etc. The Italian fem. form merged into Amelia.
Colloquial pronunciation "Ameri-kay," not uncommon 19c., goes back to at least 1643 and a poem that rhymed the word with away. Amerika "U.S. society viewed as racist, fascist, oppressive, etc." is attested from 1969; the spelling is German but it also might suggest the KKK.