- nebula
- c.1420, nebule "a cloud, mist," from L. nebula "mist," from PIE *nebh- "cloud, vapor, fog, moist, sky" (cf. Skt. nabhas- "vapor, cloud, mists, fog, sky;" Gk. nephele, nephos "cloud;" Ger. nebel "fog;" O.E. nifol "dark;" Welsh niwl "cloud, fog;" Slav. nebo). Re-borrowed from L. 1661 in sense of "cataracts in the eye;" astronomical meaning "cloud-like patch in the night sky" first recorded c.1730. As early as Hershel (1802) astronomers realized that some nebulae were star clusters, but distinction of gas clouds from distant galaxies was not made until c.1930.