Pronunciation: (neb'yu-lu),[key] —n., —pl.-laePronunciation: (-lē", -lī"),[key]-las. 1. Astron. a. Also called diffuse nebula. a cloud of interstellar gas and dust. Cf. dark nebula, emission nebula, reflection nebula. b. (formerly) any celestial object that appears nebulous, hazy, or fuzzy, and extended in a telescope view.
2. Pathol. a. a faint opacity in the cornea.
b. cloudiness in the urine.
3. any liquid medication prepared for use as a spray.