1550s, with reference to More's fictional country; 1610s as "extravagantly ideal, impossibly visionary," from utopia + -an. As a noun meaning "visionary idealist" it is recorded by 1832 (also in this sense was utopiast, 1845). Utopian socialism is from 1849, originally pejorative, in reference to the Paris uprising of 1848; also a dismissive term in communist jargon, in reference to the ideas of Fourier, St. Simon, and Owen, "the pre-scientific and infantile stage" of modern, practical socialism.
c. 1600, "not real," from un- (1) "not" + real (adj.). Meaning "impractical, visionary" is by 1660s. Slang sense of "wonderful, great" is first recorded 1965.
Unreal City,
Under the brown fog of a winter dawn,
A crowd flowed over London Bridge, so many,
I had not thought death had undone so many.
[Eliot, from "The Waste Land," 1922]
mid-13c., dremen, "to have a dream or dreams, be partly and confusedly aware of images and thoughts during sleep," from dream (n.). Transitive sense of "see in a dream" is from c. 1300. Sense of "think about idly, vainly, or fancifully; give way to visionary expectation" is from late 14c. Related: Dreamed; dreaming. To dream up "picture (something) in one's mind" is by 1941.
In the older sense of "sing, rejoice, play music," it is from Old English drēman (Anglian); dryman (West Saxon), from the Old English noun. This was obsolete from c. 1300.
c. 1300, "invisible gases that surround the earth," from Old French air "atmosphere, breeze, weather" (12c.), from Latin aer "air, lower atmosphere, sky," from Greek aēr (genitive aeros) "mist, haze, clouds," later "atmosphere" (perhaps related to aenai "to blow, breathe"), which is of unknown origin. It is possibly from a PIE *awer- and thus related to aeirein "to raise" and arteria "windpipe, artery" (see aorta) on notion of "lifting, suspended, that which rises," but this has phonetic difficulties.
In Homer mostly "thick air, mist;" later "air" as one of the four elements. Words for "air" in Indo-European languages tend to be associated with wind, brightness, sky. In English, air replaced native lyft, luft (see loft (n.)). In old chemistry, air (with a qualifying adjective) was used of any gas.
To be in the air "in general awareness" is from 1875; up in the air "uncertain, doubtful" is from 1752. To build castles in the air "entertain visionary schemes that have no practical foundation" is from 1590s (in 17c. English had airmonger "one preoccupied with visionary projects"). Broadcasting sense (as in on the air, airplay) first recorded 1927. To give (someone) the air "dismiss" is from 1900. Air pollution is attested by 1870. Air guitar is by 1983. Air traffic controller is from 1956.
of persons, "extravagantly chivalrous, absurdly romantic," abstractly, "striving for an unattainable or impractical ideal," 1791, from Don Quixote, the romantic, impractical hero of Cervantes' satirical novel "Don Quixote de la Mancha" (1605; in English translation by 1620). Don Quixote as the type of anyone attempting the impossible or holding visionary but impossible ideals is in English from 1670s.
His name literally means "thigh," also "a cuisse" (a piece of armor for the thigh), in Modern Spanish quijote, from Latin coxa "hip" (see coxa). Related: Quixotical; quixotically.
Cervantes smiled Spain's chivalry away;
A single laugh demolish'd the right arm
Of his own country; — seldom since that day
Has Spain had heroes.
[Byron, "Don Juan"]
late Old English castel "village" (this sense from a biblical usage in Vulgar Latin); later "large building or series of connected buildings fortified for defense, fortress, stronghold" (late Old English), in this sense from Old North French castel (Old French chastel, 12c.; Modern French château), from Latin castellum "a castle, fort, citadel, stronghold; fortified village," diminutive of castrum "fort," from Proto-Italic *kastro- "part, share;" cognate with Old Irish cather, Welsh caer "town" (probably related to castrare via notion of "cut off," from PIE root *kes- "to cut"). In early bibles, castle was used to translate Greek kome "village."
Latin castrum in its plural castra was used for "military encampment, military post" and thus it came into Old English as ceaster and formed the -caster and -chester in place names. Spanish alcazar "castle" is from Arabic al-qasr, from Latin castrum. Castles in Spain "visionary project, vague imagination of possible wealth" translates 14c. French chastel en Espaigne (the imaginary castles sometimes stood in Brie, Asia, or Albania) and probably reflects the hopes of landless knights to establish themselves abroad. The statement that an (English) man's home is his castle is from 16c.
THAT the house of every man is to him as his castle and fortress, as well for his defence against injuries and violence, as for his repose .... [Edward Coke, "Semaynes Case," 1604]