dollar

Etymology

Attested since about 1500, from early Dutch daler, daalder, from German Taler, Thaler (“dollar”), from Sankt Joachimsthaler, literally "of Joachimstal," the name for coins minted in German Sankt Joachimsthal (“St. Joachim's Valley”) (now Jáchymov, Czech Republic). Ultimately from Joachim + Tal (“valley”). Cognate to Danish daler. Doublet of taler.

noun

1. Official designation for currency in some parts of the world, including Canada, the United States, Australia, New Zealand, Hong Kong, and elsewhere. Its symbol is $.
   Yeah, but why? Lincoln doesn’t need the penny for notoriety. He’s everywhere. We put him on novelty bandages, cup-and-ball games, and creepy Chia Pets. And you know where else we put him? The five-dollar bill! You know, the thing that’s worth 500 times more than the penny! Nov 22 2015, “Pennies”, in Last Week Tonight with John Oliver, season 3, episode 35, John Oliver (actor), via HBO
2. (by extension) Money generally.
   Television, a favored source of news and information, pulls the largest share of advertising monies. In 1935, newspapers received 45 percent of the advertising dollar, magazines 8 percent, and radio 7 percent. 2002, Marcella Ridlen Ray, Changing and Unchanging Face of United States Civil Society
3. (UK, colloquial, historical) A quarter of a pound or one crown, historically minted as a coin of approximately the same size and composition as a then-contemporary dollar coin of the United States, and worth slightly more.
   We like to go down to restaurant row / Spend those euro-dollars / All the way from Washington to Tokyo October 28 1990, Paul Simon, “Born at the Right Time”, in The Rhythm of the Saints, Warner Bros.
   But poverty’s scourge is fiercest below $1.25 (the average of the 15 poorest countries’ own poverty lines, measured in 2005 dollars and adjusted for differences in purchasing power): people below that level live lives that are poor, nasty, brutish and short. 2013-06-01, “Towards the end of poverty”, in The Economist, volume 407, number 8838, page 11
4. (attributive, historical) Imported from the United States, and paid for in U.S. dollars. (Note: distinguish "dollar wheat", North American farmers' slogan, meaning a market price of one dollar per bushel.)
   The restricted purchase of dollar tobacco will, we hope, have the effect of increasing the imports of Turkish and Grecian tobacco 1952 Brigadier Sir Harry Mackeson, House of Commons, London; Hansard, vol 504, col 271, 22 July 1952
   For there are two luxury imports that lead all the others: dollar films and dollar tobacco. 1956, The Spectator, volume 197, page 342
5. (nuclear physics) A unit of reactivity equal to the interval between delayed criticality and prompt criticality.