NEBULA

Neb″u‐la (nĕb″ū̍‐lȧ), n.; pl. Nebulæ (#). [[L., mist, cloud; akin to Gr. νεφέλη, νέφοσ, cloud, mist, G. nebel mist, OHG. nebul, D. nevel, Skr. nabhas cloud, mist. Cf. Nebule.]] 1. 1. (Astron.) A faint, cloudlike, self-luminous mass of matter situated beyond the solar system among the stars. True nebulæ are gaseous; but very distant star clusters often appear like them in the telescope.
2. 2. (Med.) (a) A white spot or a slight opacity of the cornea. (b) A cloudy appearance in the urine.