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" (cognates: Avestan snaoda "clouds," Latin obnubere "to veil," Welsh nudd "fog," Greek nython, in Hesychius "dark, dusky"). According to Klein, a reference to "the different colors of the clouds."