as an annual ecological awareness event on April 22, from 1970; the idea for it and the name date from 1969.

Old English Pentecosten "Christian festival on seventh Sunday after Easter," from Late Latin pentecoste, from Greek pentekostē (hēmera) "fiftieth (day)," fem. of pentekostos, from pentekonta "fifty," from pente "five" (from PIE root *penkwe- "five"). The Hellenic name for the Old Testament Feast of Weeks, a Jewish harvest festival observed on 50th day of the Omer (see Leviticus xxiii.16).

region in northeastern Germany, traditionally said to be ultimately from Slavic, but perhaps German and meaning literally "burned fortress," or else from a Celtic proper name. In reference to a kind of ornamental button with loops, worn on the front of men's coats, by 1753, probably from Prussian military uniforms; later extended to ornamental buttons on women's dress (1873).

European dynasty, from German Habsburg, from the name of a castle on the Aar in Switzerland, originally Habichtsburg, literally "Hawk's Castle."

1727, Swift's name in "Gulliver's Travels" for an imaginary country where everything was on a gigantic scale. Not *brobdignag.

1871, in reference to Christian Doppler (1803-1853), Austrian scientist, who in 1842 explained the effect of relative motion on waves (originally to explain color changes in binary stars); proved by musicians performing on a moving train. Doppler shift (1955) is the change of frequency resulting from the Doppler effect (1894). The surname is literally "Gambler."

proprietary name of a drink mix, 1906, probably based on Latin ovum "egg" (see ovary), because eggs are one of the ingredients.

1968, acronym from fictitious "Youth International Party," modeled on hippie.

On December 31, 1967, Abbie [Hoffman], Jerry [Rubin], Paul Krassner, Dick Gregory, and friends decided to pronounce themselves the Yippies. (The name came first, then the acronym that would satisfy literal-minded reporters: Youth International Party.) [Todd Gitlin, "The Sixties," 1987, p.235]

city on the French coast of the English Channel, from Gaulish Caleti, the name of a Celtic people who once lived along the shore there.

commercially important synthetic polymer, 1945, proprietary name registered in U.S. by du Pont, from chemical name (poly)te(tra)fl(uoroethylene) + arbitrary ending -on; popularized as a coating of non-stick pans in 1960s; metaphoric extension, especially in reference to U.S. President Ronald Reagan, is attested from an Aug. 2, 1983, speech on the floor of Congress by Pat Schroeder.