Old English mistian "to become misty, to be or grow misty;" see mist (n.). Meaning "cover with or as with mist" is from early 15c. Related: Misted; misting.
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.
1754, "cloudiness, haziness," from French nébulosité, from Late Latin nebulositatem (nominative nebulositas), from Latin nebulosus, from nebula "mist, vapor" (from PIE root *nebh- "cloud"). From 1761 as "faint, misty appearance surrounding certain stars."
"a spider's web," early 14c., coppewebbe; the first element is Old English -coppe, in atorcoppe "spider," literally "poison-head" (see attercop). Spelling with -b- is from 16c., perhaps from cob. Cob as a stand-alone for "a spider" was an old word nearly dead even in dialects when J.R.R. Tolkien used it in "The Hobbit" (1937).
Figurative use for "something flimsy and easily broken through" is by 1570s. Plutarch attributes to Anacharsis, the 6c. B.C.E. Scythian-born philosopher in Athens, the statement, variously given, that laws were like cobwebs that entangled the little flies but wasps and hornets never failed to break through them. An old Norfolk term for a misty morning was cobweb-morning (1670s).
Middle English reke "smoke, fumes; steam, vapor," from Old English rec (Anglian), riec (West Saxon), "smoke from burning material," probably from a Scandinavian source such as Old Norse reykr, Danish rǿg, Swedish rök "smoke, steam."
These are reconstructed to be from Proto-Germanic *raukiz (source also of Old Frisian rek, Middle Dutch rooc, Old High German rouh, German Rauch, Icelandic reykr "smoke, steam"), from PIE *reug- "to vomit, belch;" also "smoke, cloud."
The sense of "stench" is attested 1650s via the notion of "that which rises" (compare reek (v.)). Century Dictionary (1891) marks the word "Obsolete, archaic, or Scotch." According to OED, "As the word has chiefly survived in northern use the palatalized form reech is comparatively rare." A c. 1250 document refers to the period March-April as Reke-fille "the misty month."
"partial darkness, state between light and darkness, twilight," 1620s, from an earlier adjective dusk, from Middle English dosc (c. 1200) "obscure, not bright; tending to darkness, shadowy," having more to do with color than light, which is of uncertain origin, not found in Old English. Middle English also had it as a verb, dusken "to become dark." The Middle English noun was dusknesse "darkness" (late 14c.).
Perhaps it is from a Northumbrian variant of Old English dox "dark-haired, dark from the absence of light," with transposition of -k- and -s-, (compare colloquial ax for ask). But OED notes that "few of our words in -sk are of OE origin." Old English dox is from PIE *dus-ko- "dark-colored" (source also of Swedish duska "be misty," Latin fuscus "dark," Sanskrit dhusarah "dust-colored;" also compare Old English dosan "chestnut-brown," Old Saxon dosan, Old High German tusin "pale yellow").
"weather condition consisting of a cloud resting upon the ground, fog," also "precipitation consisting of fine droplets of water, much smaller than rain," Old English mist (earliest in compounds, such as misthleoðu "misty cliffs," wælmist "mist of death"), from Proto-Germanic *mikhstaz (source also of Middle Low German mist, Dutch mist, Icelandic mistur, Norwegian and Swedish mist), perhaps from PIE *meigh- "to urinate." Greek omikhle "fog;" Old Church Slavonic migla"fog;" Sanskrit mih- "fog, mist," megha "cloud" sometimes are said to be cognates in this secondary sense, but Beekes finds these rather more likely to be from a separate IE root meaning "fog."
Sometimes distinguished from fog, either as being less opaque or as consisting of drops large enough to have a perceptible downward motion. [OED]
Also in Old English in reference to dimness of the eyes or eyesight, either by illness or tears, and in a figurative sense of "something that darkens and obscures mental vision." Meaning "haze of dust in the air producing obscurity of things seen at a distance" is by 1785.