late 14c., "cloudy, misty, hazy" (of the eye, fire-smoke, etc.), from Latin nebulosus "cloudy, misty, foggy, full of vapor," from nebula "mist, vapor" (from PIE root *nebh- "cloud"). The figurative sense of "hazy, vague, formless" is attested by 1831. Astronomical sense, in reference to stars or star clusters surrounded by luminous haze, is from 1670s. Related: Nebulously; nebulousness.
"slight or delicate degree of difference in expression, feeling, opinion, etc.," 1781, from French nuance "slight difference, shade of color" (17c.), from nuer "to shade," from nue "cloud," from Gallo-Roman *nuba, from Latin nubes "a cloud, mist, vapor," from PIE *sneudh- "fog" (source also of Avestan snaoda "clouds," Latin obnubere "to veil," Welsh nudd "fog," Greek nython, in Hesychius "dark, dusky").
According to Klein, the French secondary sense is a reference to "the different colors of the clouds." In reference to color or tone, "a slight variation in shade," by 1852; of music, by 1841 as a French term in English.
1540s, transitive, "shed in small drops;" 1560s, intransitive, "fall in very fine particles, as water from the clouds," of uncertain origin. Perhaps it is an alteration of drysning "a falling of dew" (c. 1400), from Old English -drysnian, which is related to dreosan "to fall" (see dreary). Or perhaps it is a frequentative of Middle English dresen "to fall," from Old English dreosan. Related: Drizzled; drizzling.
As a noun, "a light rain, mist," from 1550s.
1540s, of the air, "full of thick mist," perhaps from a Scandinavian source, or formed from fog (n.1) + -y (2). Foggy Bottom "U.S. Department of State," is from the name of a marshy region of Washington, D.C., where many federal buildings are (also with a suggestion of political murkiness) popularized 1947 by James Reston in the New York Times, but he said it had been used earlier by Edward Folliard of The Washington Post.
"low spirits; dull, gloomy state of mind," 1520s, plural of dumpe "a fit of musing," of uncertain origin, possibly from Dutch domp "haze, mist," from Middle Dutch damp "vapor" (see damp (n.)). Compare vapors under vapor.
The application of this term to an affection of the mind is a part of the medical theory which attributed all disorders of the frame to a humour falling on the part affected, and regarded mental disorders especially as produced by a vapour rising from the stomach into the brain. [Hensleigh Wedgwood, "A Dictionary of English Etymology," 1859]
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.
European plant growing parasitically on certain trees, Old English mistiltan, from mistel "mistletoe" (see missel) + tan "twig," from Proto-Germanic *tainan "twig" (source also of Old Saxon and Old Frisian ten, Old Norse teinn, Dutch teen, Old High German zein, Gothic tains "twig"). Similar formation in Old Norse mistilteinn, Norwegian misteltein, Danish mistelten.
Venerated by the Druids, especially when found growing on the oak, which it seldom does; the custom of hanging it at Christmas and kissing under it is mentioned by Washington Irving. The alteration of the ending according to Century Dictionary is perhaps from a mistaking of the final -n for a plural suffix after tan fell from use as a separate word, but OED finds it a natural evolution in West Saxon based on stress.