"water that has fallen from the clouds as rain and has not sunk into the earth," Old English renwæter; see rain (n.) + water (n.1).

word-forming element meaning "like or of the nature of cumulus clouds," 1887, from cumulus. Cumulo-stratus is from 1803; Cumulo-nimbus is attested by 1859.

"to cover or overspread with clouds," also figurative, "to cover with gloom or sorrow," 1590s, from over- + cloud (v.). Related: Overclouded; overclouding.

word-forming element meaning, in meteorology, "involving cirrus clouds," and, in biology, "involving a tendril or tendrils," from combining form of Latin cirrus "lock of hair, tendril" (see cirrus).

also earth-light, "sunlight reflected from Earth's surface and clouds," especially as illuminating the otherwise dark part of the moon, 1810, from earth (n.) + light (n.). Earthshine in same sense is from 1814.

1708, "curl-like fringe or tuft," from Latin cirrus "a lock of hair, tendril, curl, ringlet of hair; the fringe of a garment." In meteorology, in reference to light, fleecy clouds, attested from 1803; so called from fancied resemblance of shape.

"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.

"a flash or gleam of light," as of the reflection of lightning on clouds or moonlight on the sea, late 15c. (Caxton, choruscacyon), from Late Latin coruscationem (nominative coruscatio), noun of action from past-participle stem of Latin coruscare "to vibrate, glitter" (see coruscate).