mid-14c., "what is known, knowledge (of something) acquired by study; information;" also "assurance of knowledge, certitude, certainty," from Old French science "knowledge, learning, application; corpus of human knowledge" (12c.), from Latin scientia "knowledge, a knowing; expertness," from sciens (genitive scientis) "intelligent, skilled," present participle of scire "to know," probably originally "to separate one thing from another, to distinguish," related to scindere "to cut, divide" (from PIE root *skei- "to cut, split;" source also of Greek skhizein "to split, rend, cleave," Gothic skaidan, Old English sceadan "to divide, separate").
From late 14c. in English as "book-learning," also "a particular branch of knowledge or of learning;" also "skillfulness, cleverness; craftiness." From c. 1400 as "experiential knowledge;" also "a skill, handicraft; a trade." From late 14c. as "collective human knowledge" (especially that gained by systematic observation, experiment, and reasoning). Modern (restricted) sense of "body of regular or methodical observations or propositions concerning a particular subject or speculation" is attested from 1725; in 17c.-18c. this concept commonly was called philosophy. Sense of "non-arts studies" is attested from 1670s.
Science, since people must do it, is a socially embedded activity. It progresses by hunch, vision, and intuition. Much of its change through time does not record a closer approach to absolute truth, but the alteration of cultural contexts that influence it so strongly. Facts are not pure and unsullied bits of information; culture also influences what we see and how we see it. Theories, moreover, are not inexorable inductions from facts. The most creative theories are often imaginative visions imposed upon facts; the source of imagination is also strongly cultural. [Stephen Jay Gould, introduction to "The Mismeasure of Man," 1981]
In science you must not talk before you know. In art you must not talk before you do. In literature you must not talk before you think. [John Ruskin, "The Eagle's Nest," 1872]
The distinction is commonly understood as between theoretical truth (Greek epistemē) and methods for effecting practical results (tekhnē), but science sometimes is used for practical applications and art for applications of skill. To blind (someone) with science "confuse by the use of big words or complex explanations" is attested from 1937, originally noted as a phrase from Australia and New Zealand.
"sequence of sensations or images passing through the mind of a sleeping person," mid-13c., probably related to Old Norse draumr, Danish drøm, Swedish dröm, Old Saxon drom "merriment, noise," Old Frisian dram "dream," Dutch droom, Old High German troum, German Traum "dream." These all are perhaps from a Proto-Germanic *draugmas "deception, illusion, phantasm" (source also of Old Saxon bidriogan, Old High German triogan, German trügen "to deceive, delude," Old Norse draugr "ghost, apparition"). Possible cognates outside Germanic are Sanskrit druh- "seek to harm, injure," Avestan druz- "lie, deceive."
Old English dream meant "joy, mirth, noisy merriment," also "music." Much study has failed to prove that Old English dream is the source of the modern word for "sleeping vision," despite being identical in form. Perhaps the meaning of the word changed dramatically, or "vision" was an unrecorded secondary Old English meaning of dream, or there are two words here.
OED offers this theory for the absence of dream in the modern sense in the record of Old English: "It seems as if the presence of dream 'joy, mirth, music,' had caused dream 'dream' to be avoided, at least in literature, and swefn, lit. 'sleep,' to be substituted ...."
The dream that meant "joy, mirth, music" faded out of use after early Middle English. According to Middle English Compendium, the replacement of swefn (Middle English swevn) by dream in the sense "sleeping vision" occurs earliest and is most frequent in the East Midlands and the North of England, where Scandinavian influence was strongest.
Dream in the sense of "that which is presented to the mind by the imaginative faculty, though not in sleep" is from 1580s. The meaning "ideal or aspiration" is from 1931, from the earlier sense of "something of dream-like beauty or charm" (1888). The notion of "ideal" is behind dream girl (1850), etc.
Before it meant "sleeping vision" Old English swefn meant "sleep," as did a great many Indo-European "dream" nouns originally, such as Lithuanian sapnas, Old Church Slavonic sunu, and the Romanic words (French songe, Spanish sueño, Italian sogno all from Latin somnium. All of these (including Old English swefn) are from PIE *swep-no-, which also is the source of Greek hypnos (from PIE root *swep- "to sleep"). Old English also had mæting in the "sleeping vision" sense.
"monetary unit or standard of value in the U.S. and Canada," 1550s, daler, originally in English the name of a large, silver coin of varying value in the German states, from Low German daler, from German taler (1530s, later thaler), abbreviation of Joachimstaler, literally "(gulden) of Joachimstal," coin minted 1519 from silver from mine opened 1516 near Sankt Joachimsthal, town in Erzgebirge Mountains in northwest Bohemia. German Tal is cognate with English dale. The spelling had been modified to dollar by 1600.
The thaler was from 17c. the more-or-less standardized coin of northern Germany (as opposed to the southern gulden). It also served as a currency unit in Denmark and Sweden (and later was a unit of the German monetary union of 1857-73 equal to three marks).
English colonists in America used the word dollar from 1580s in reference to Spanish peso or "piece of eight," also a large silver coin of about the same fineness as the thaler. Due to extensive trade with the Spanish Indies and the proximity of Spanish colonies along the Gulf Coast, the Spanish dollar probably was the coin most familiar in the American colonies and the closest thing to a standard in all of them.
When the Revolution came, it had the added advantage of not being British. It was used in the government's records of public debt and expenditures, and the Continental Congress in 1786 adopted dollar as a unit when it set up the modern U.S. currency system, which was based on the suggestion of Gouverneur Morris (1782) as modified by Thomas Jefferson. None were circulated until 1794.
When William M. Evarts was Secretary of State he accompanied Lord Coleridge on an excursion to Mount Vernon. Coleridge remarked that he had heard it said that Washington, standing on the lawn, could throw a dollar clear across the Potomac. Mr. Evarts explained that a dollar would go further in those days than now. [Walsh]
Phrase dollars to doughnuts "an assured thing, a certainty" (such that one would bet a dollar against a doughnut on it) is attested by 1884; dollar diplomacy "financial imperialism, foreign policy based on financial and commercial interests" is from 1910.
The dollar sign ($) is said to derive from the image of the Pillars of Hercules, stamped with a scroll, on the Spanish piece of eight. However, according to the Bureau of Engraving and Printing of the U.S. Department of the Treasury:
[T]he most widely accepted explanation is that the symbol is the result of evolution, independently in different places, of the Mexican or Spanish "P's" for pesos, or piastres, or pieces of eight. The theory, derived from a study of old manuscripts, is that the "S" gradually came to be written over the "P," developing a close equivalent of the "$" mark. It was widely used before the adoption of the United States dollar in 1785.